Lidar systems based on single-photon avalanched diode(SPAD) array detector not only have high sensitivity and time resolution, but also have high detection rate. It has wide application prospects in the fields of remote sensing mapping, target recognition, spacecraft landing and so on. Due to the shortcomings of the current SPAD array devices, such as the small pixel format and the hot pixel problems, the quality of the three-dimensional(3D) images obtained by directly using the SPAD array is poor and the imaging area is small. A continuous scanning three-dimensional imaging method with SPAD array based on pixel multiplexing was proposed to expand the imaging area. At the same time, the multiplexing of pixel information could increase the cumulative detection times of the same target point, thereby improving the depth measurement accuracy and the 3D imaging quality. A push-broom imaging experimental system was established based on a 32×32 SPAD array. By performing a one-dimensional continuous scanning imaging experiment on a target 3.3 m away, a fast and large-scale photon counting 3D imaging(32 rows×520 columns/7 s) was achieved. Meanwhile, the influence of hot pixels on the imaging results is effectively alleviated, and the plane accuracy of the three-dimensional image achieves 2.3 mm.