Abstract: In order to study the improvement of surveying accuracy by tilt photogrammetry, taking two survey areas A and B as an example, the two-piece and multi-piece intersection, vertical and tilt images are used as contrast conditions to establish a stereoscopic model and a real scene 3D model. Through the error statistics of the checkpoints in the models and digital line graphic, the plane accuracy and elevation accuracy are compared and analyzed. Compared with the stereoscopic model based on the two-piece front intersection, the real scene 3D model based on the multi-piece front intersection has higher accuracy. In the survey area A where the terrain is highly mountainous, the errors in plane and elevation are increased from decimeter level to centimeter level, and combining with Specifications for Aerotriangulation of Digital Aerophotogrammetry, it can reach the mapping standard of 1:500 scale. Compared with vertical photogrammetry, oblique photogrammetry has more intersection rays, so its model accuracy is higher. In the survey area B where the terrain is mountainous, the elevation accuracy can be equivalent to the plane accuracy, and the median error is within 5 cm, which solves the problem of poor elevation accuracy in aerial photogrammetry due to image acquisition methods, and by 3D mapping based on the tilted real 3D model, the error in the contour meets the accuracy requirements of the 1:500 scale in Specifications for Aerophotogrammetric Office Operation of 1:500 1:1 000 1:2 000 Topographic Maps.

Key words: tilt photogrammetry, scene 3D model, precision analysis