Transparent objects such as glass and lenses are commonly used in optical systems, and their surface quality greatly affects the performance of the host systems. Considering polarization characteristics of light, surface defect detection method using polarized transmission structured light is proposed. The constructed transmission system generates fringe-encoded polarized structured light for projection onto the surface of the measured object. The structured light deforms after passing through the object. Then, the deformation fringes are collected, phase information is extracted, modulation is solved, and surface defect information is obtained from the measured object. Experimental results show that the proposed method can eliminate the effect of dust and improve the signal-to-noise ratio for detection. Therefore, the proposed method can be suitable for surface defect detection in transparent objects such as flat thick lenses and high-curvature optical lenses.