Abstract: Resistance spot welded joints (RSW joints) of DP980-DP980, DP980-QP980 and QP980-QP980 welding combinations under the condition of 5 \sqrtt nugget diameters were taken as research object. After being baked at 170 ℃ for 20 minutes, RSW joints were subjected to tensile shear test, cross tensile test, scanning electron microscopy observation, and microhardness testing. Effect of baking on mechanical properties of RSW joints of 980 MPa advanced high strength steel was analyzed. The result showed that baking further increased the peak tensile shear load of each combination, and absorbed energy of RSW joints increased by more than 10%. In terms of cross tensile, RSW joints of the three combinations have similar energy absorption after baking. For DP980-QP980 and QP980-QP980 RSW joints, cross tensile strength after baking increased by 56% and 63%, and absorbed energy increased by 27% and 67%, respectively. Tensile and shear failure modes of the three combinations did not show significant changes before and after baking, while cross tensile failure mode of DP980-QP980 after baking showed a trend of crack propagation path shifting from fusion line to base metal on the QP980 side. Baking resulted in a certain tempering characteristic of metallographic structure of RSW joints and a certain decrease in hardness of nugget, but it was not significant.