The utility model discloses a locking device of a two-dimensional space scanning mechanism. The locking device is applied to the technical field of aerospace. The locking device comprises a base, a check block assembly, a pin pulling device, a rotator connection frame and a tension spring, wherein the base is installed on a foundation support of the scanning mechanism, the check block assembly, the pin pulling device and the tension spring are all installed on the base, one end of the rotator connection frame is fixedly connected with a two-dimensional mechanism rotator, one end of the rotator connection frame is matched with a pin shaft, a check block is a movable component and a rotary shaft is a check block shaft. When locking is carried out, a pin shaft of the pin pulling device penetrates through a bush of the base, a bush of the rotator connection frame and a bush of the pin shaft, then the pin shaft of the pin pulling device and the check block assembly lock the mechanism rotator, and the tension spring is in a tensioned state; during unlocking, the pin shaft is pulled out, and the check block returns to an original position around the check shaft under the action of tension spring force to finish unlocking. The locking device is characterized in that two-dimensional locking of the scanning mechanism is achieved through the locking device. The locking device is convenient to disassemble and assemble, simple in structure, safe and reliable, and provides an effective locking mode of the space two-dimensional scanning mechanism.