A lock assembly for a battery lock-up mechanism, the battery lock-up mechanism further comprises a fixing assembly which is adapted to be connected to a new energy vehicle, the lock assembly comprising: a hollow casing which is opened at a bottom end and has a first through hole at a top end, wherein a washer is disposed in the first through hole; wherein the lock assembly further comprises a stop end plate formed with a second through-hole at the center of the stop end plate and formed with a groove in an indexed arrangement that passes through the second through-hole, the stop end plate and the casing engaging with each other to define an accommodation space; and a hollow central pull shaft having a columnar portion, a lug portion, and a flange portion between the columnar portion and the lug portion, the columnar portion having a closed top end that passes through the second through hole of the stop end plate and the first through hole of the casing, the closed top end having a first connection structure in form of an external thread configured to engage with a second connection structure on the fixing assembly, a relative axial movement of the fixing assembly and the lock assembly can be restricted through the engagement of the first connection structure and the second connection structure, the columnar portion being formed with a radially penetrating notch at a position adjacent to the flange portion, and the flange portion having a diameter larger than the diameter of the columnar portion and the diameter of the lug portion, and also larger than the diameter of the second through hole; the lock assembly further comprises a return spring, a push rod and a locking pin, wherein: the return spring is positioned in the central pull shaft, one end of the push rod has a radially penetrating third through hole and extending into the central pull shaft, another end of the push rod extends out of the central pull shaft from the lug portion, the return spring urges the push rod, and the locking pin passes through the radially penetrating notch of the columnar portion of the hollow central pull shaft notch and the third through hole of the push rod in the accommodation space. a hollow casing which is opened at a bottom end and has a first through hole at a top end, wherein a washer is disposed in the first through hole; wherein the lock assembly further comprises a stop end plate formed with a second through-hole at the center of the stop end plate and formed with a groove in an indexed arrangement that passes through the second through-hole, the stop end plate and the casing engaging with each other to define an accommodation space; and a hollow central pull shaft having a columnar portion, a lug portion, and a flange portion between the columnar portion and the lug portion, the columnar portion having a closed top end that passes through the second through hole of the stop end plate and the first through hole of the casing, the closed top end having a first connection structure in form of an external thread configured to engage with a second connection structure on the fixing assembly, a relative axial movement of the fixing assembly and the lock assembly can be restricted through the engagement of the first connection structure and the second connection structure, the columnar portion being formed with a radially penetrating notch at a position adjacent to the flange portion, and the flange portion having a diameter larger than the diameter of the columnar portion and the diameter of the lug portion, and also larger than the diameter of the second through hole; the lock assembly further comprises a return spring, a push rod and a locking pin, wherein: the return spring is positioned in the central pull shaft, one end of the push rod has a radially penetrating third through hole and extending into the central pull shaft, another end of the push rod extends out of the central pull shaft from the lug portion, the return spring urges the push rod, and the locking pin passes through the radially penetrating notch of the columnar portion of the hollow central pull shaft notch and the third through hole of the push rod in the accommodation space.