Abstract: In this study, Gleeble-3500 thermal simulation system was used to simulate the different sub-regions of the heat affected zone of QP980 quenching-partitioning steel laser welding. The microstructure and properties of each sub-zone were studied and compared with the same area of the heat affected zone of the welded joint. The results showed that the microstructure of each sub-region of the welding heat affected zone obtained by thermal simulation is consistent with that of the same region of the laser welded joints. The mechanical properties analysis showed that the tensile strength and hardness of the sub-critical heat affected zone(SCHAZ) are the lowest in the thermal simulation samples, and the elongation after fracture is the largest in the whole welding heat affected zone. In the tensile test, obvious elongation also occurred in this area, indicating that its ductility was the best. The hardness analysis of the cross section of the welded joint showed that the hardness of the inter-critical heat affected zone(ICHAZ)of the welded joint is lower than that of the base metal(BM), which is the softening zone of the welded joint. The tensile properties and cross-sectional hardness distribution of the welded joint showed that the weak area of the welded joint is located in the ICHAZ, which is consistent with the performance of the simulated welding heat affected zone. Through the analysis of the microstructure of the SCHAZ, compared with the BM, the geometrically necessary dislocations (GND) must be reduced, the average grain size is increased, and the small angle grain content is decreased.