Abstract: The microstructure, phase composition and mechanical properties of hot rolled C-Mn-Si transformation-induced plasticity (TRIP) steel which was low-alloyed with Nb and V were investigated by means of electron back scatter diffraction (EBSD). It is found that the deformation of austenite by hot rolling and the cooling process followed has direct impact on the microstructure concerning the shape, size, and distribution of ferrite, bainite and retained austenite, which determines the ultimate mechanical properties of the TRIP steel. The simulated results for coiling temperature of the TRIP steel show that the hot strips coiled at 400℃ obtain the best comprehensive mechanical properties compared to those coiled at 450 and 350℃.