The main task for High Flux Engineering Test Reactor(HFETR) is to carry out the irradiation test of nuclear materials. The premise of the irradiation is the accurate calculation of the neutron flux. This paper introduces the neutron flux calculation method of irradiation on HFETR,and the method is verified by the test in P15 channel. The calculation data were compared with the measurement value, and the numerical results demonstrated that the deviation of calculation data was 7.14%, which satisfied the requirement of material irradiation test.