Evaluation of object 3D shape change during ablation in wind tunnel test is critical for optimization of thermal protection system. However, strong thermal radiation and harsh environment bring challenges to the traditional measurement methods. A single camera DMD-projector structured laser light system is proposed for in-situ 3D shape measurement in wind tunnel test. A customized Digital Micro-Mirror Device (DMD) combined with laser source is devised for projecting concentrated full-field high-power structured light stripes. To filter laser speckle noise in projected chessboard images for model calibration, an auto-window Kuwahara adaptive filter is put forward. 3D shape of a blunt-head cylinder was in-situ measured in a plasma wind tunnel which maximum temperature reached 1950℃. Diameter reconstruction error was within 0.85% (0.17/20.03mm). With projected laser light and multi-step filters, ablation process of front face of a dome-top cylinder at 1950℃ was clearly observed at a long working distance over 1.5m.