The welding test of CSP hot rolled DP600 is carried out with resistance spot welding,relatively good welding parameters are obtained,and the cross tensile force,microstructure and microhardness of the welding spot are studied. The results show that adopting single phase AC spot welding technology, welding current is between 8.9 kA and 12.2 kA, the microstructure of weld is mainly lath martensite. The diameter and cross tensile force of welding spot firstly increase and then decrease as the welding current increase.The microhardness of the weld metal zone of the welded joint is the highest,and it decreases as the welding heat input increases.There was no obvious hardening or softening phenomenon in the heat affected zone.