Traditional three-dimensional imaging methods can be categorized into active imaging and passive imaging based on the presence of illumination sources. Structured light technology,as a form of active imaging,does not perform satisfactorily in imaging surfaces of objects without texture or lacking texture. Passive polarized three-dimensional imaging technology offers an effective imaging method for such objects,yet it still encounters challenges related to sensitivity to noise and ambiguity in reconstruction. In response to the limitations of a single mode,this study proposes a three-dimensional reconstruction method that combines active structured light with passive polarization.The initial step in obtaining polarised images is to rotate a polariser to capture different polarisation states. Subsequently,the images are subjected to denoising and the calculation of polarization degree,polarization angle,and zenith angle,to reduce noise's impact on polarization information significantly. This results in an ambiguous azimuth angle. To address this ambiguity,structured light is employed to obtain a point cloud and depth images of the object under examination. The gradient information of the depth image in this state is obtained and used to rectify the polarization gradient information derived from the polarization information,thus eliminating ambiguities caused by the polarization angle. Subsequently,the corrected gradient information is integrated to obtain a rough relative depth map of the object,which exhibits surface roughness at this stage. To address this,the mesh data extracted from the obtained rough relative depth map is subjected to smoothing,thereby acquiring a smooth relative depth map. Finally,the fused absolute depth map of the object is obtained by combining the original point cloud from structured light with Poisson reconstruction.In this study,key points on the measured object were randomly selected and the actual physical distances between these points were compared with the distances computed by the reconstruction model. The absolute error between the calculated and measured distances was less than 0.6 mm. The relative error is less than 3%,verifying the algorithms' validity. It can be seen that the polarization active-passive fusion 3D reconstruction technique based on structured light,as proposed in this paper,not only achieves a high standard of accuracy but also shows high reliability. The application of this method provides an effective technical means for accurate 3D reconstruction of textureless objects.