The invention provides a pure electric two-speed transmission. The pure electric two-speed transmission comprises an input shaft (1), a reducer (6), an output shaft (7) and a brake (8), and a planetary mechanism which comprises a sun gear (4), a planet gear (3), a gear ring (5) and a planet carrier (2), wherein the planet carrier (2) is fixedly assembled to the input shaft (1), the sun gear (4) is fixedly assembled to the output shaft (7), and the right end of the output shaft (7) is fixedly connected with the reducer (6), the pure electric two-speed transmission is characterized by further comprising a one-way clutch (9), the right end of the output shaft (1) is connected with the left end of the output shaft (7) through the one-way clutch (9), and the gear ring (5) of the planetary mechanism is connected with the brake (8). According to the invention, gears can be shifted only by using one one-way clutch 9 and one brake 8, and one one-way clutch 9 and one brake 8 are only required to be controlled when the gears are shifted, so that the control difficulty is smaller.