The laser transport system of the high power laser facility is mainly composed of large-aperture lasertransport mirrors (TMs). Obtaining the high-resolution online damage images during the operation,which is of great significance for operating safely of the mirrors and the facility. Based on wavefrontcoding, pan-tilt scanning and image stitching technologies, an online laser-damage images detectionsystem is designed, and it can achieve high-precision detection of surface characteristics of largeaperturelaser transport mirrors. The preliminary simulation proves that the system can solve thedepth of field matching problem caused by pan-tilt tilt imaging and achieve higher resolution.