Abstract: The microstructure and high temperature tensile properties of Ni_1.5CrMnFe_0.5Al_0.2Ti_0.1C_0.02Nb_0.003 high entropy alloy were investigated after solution treatment（at 1150℃） and aging at different temperatures（625-700 ℃）. The results indicate that FCC+BCC dual-phase structure can be observed in as-cast and as-aged samples. The BCC phase is resolved after solid solution aging to form a woven network. As the aging temperature increases, the alloy hardness is gradually decreased,reaching a maximum value of 514 HV at 625 ℃, with a 147% increase relative to the casting state. The 675 ℃ aging alloy has the best high temperature performance, with the tensile strength of 526 MPa, the yield strength of 428 MPa and 22%elongation at 600 ℃ stretch.