I claim:1. A circuit board fixing base, comprisinga fixing base (2) fixed on a circuit board (1) and including a carrier (3) for carrying an electronic device (5) and an elastic locking arm (4) located beside the carrier (3), an upper end of the elastic locking arm (4) having a locking body (41) for fastening and fixing with the electronic device (5) to lock the electronic device (5) on the carrier (3), a locking space (40) for locking the electronic device (5) being formed between the locking body (41) and the carrier (3), and a guiding slope (411) being provided on an upper end of the locking body (41), wherein when the electronic device (5) is pressed on the guiding slope (411), the upper end of the elastic locking arm (4) is forced to bend and deform outward.2. The circuit board fixing base according to claim 1, wherein an outside of an upper end of the elastic locking arm (4) is configured with a handle (42).3. The circuit board fixing base according to claim 1, wherein the carrier (3) includes a base body (31) formed integrally on the fixing base (2), a limiting boss (32) formed on an upper end of the base body (31), and a bearing groove (33) formed between the periphery of the limiting boss (32) and the upper end of the base body (31);the locking body (41) is placed above the bearing groove (33), the shape of the limiting boss (32) is adapted to the shape of a positioning opening (51) at the end of the electronic device (5), and the limiting boss (32) is embedded in the positioning opening (51).4. The circuit board fixing base according to claim 1, wherein the elastic locking arm (4) is a plastic component or a die-casting component, which is fixed on the fixing base (2) through integral molding, and forms an inseparable whole with the fixing base (2).5. The circuit board fixing base according to claim 1, wherein the elastic locking arm (4) is an independent metal component, which is installed on the fixing base (2) through assembly.6. The circuit board fixing base according to claim 5, wherein the elastic locking arm (4) is in the shape of U or V, the upper end of the fixing base (2) is configured with a moving groove (21), the elastic locking arm (4) is inserted into the moving groove (21), and bends and deforms in the moving groove (21).7. The circuit board fixing base according to claim 6, wherein the elastic locking arm (4) includes a main part (43), an arch-shaped bent part (44) formed at a lower end of the main part (43), an elastic arm (45) formed on an upper end of the arch-shaped bent part (44) and the two locking bodies (41) respectively bent and formed on both sides of an upper end of the elastic arm (45), the locking body (41) is extended out of a front end of the elastic arm (45), the main part (43) is stamped to a locking plate (430) for clamping and positioning with an inner wall of the moving groove (21) for positioning.8. The circuit board fixing base according to claim 7, wherein the inner wall of the moving groove (21) is configured with a limiting slot (211), the two sides of the main part (43) are formed with a limiting plate (431) protruding outward, the limiting plate (431) is clasped and fixed on the inner wall of the limiting slot (211), so that the main part (43) can be fixed inside the moving groove (21), the elastic arm (45) is placed inside the moving groove (21), and can be bent and deformed inside the moving groove (21), the upper end of the elastic arm (45) is extended out of the upper end of the moving groove (21).9. The circuit board fixing base according to claim 1, wherein the lower end of the fixing base (2) is formed with a threaded column (22), and the circuit board (1) is fixed with a row of nuts (11), the fixing base (2) is fixed on any of the nuts (11) through the threaded column (22), so as to be fixed on the circuit board (1).10. The circuit board fixing base according to claim 9, wherein the periphery of the nut (11) is configured with a positioning groove (111), one side wall of the positioning groove (111) is configured as a first inclined guiding face (112), the lower end of the fixing base (2) is formed with a limiting convex block (23) adapted to the positioning groove (111), and the limiting convex block (23) is formed with a second inclined guiding face (231), so that the limiting convex block (23) can slide into the positioning groove (111).
