Abstract: Based on the low-power physics test results of Gen Ⅲ Passive PWR AP1000 reactor, the calculation function and calculation accuracy of the COSINE software package design software are confirmed and evaluated. From the comparison of the control rod worth, ARO (All Rods Out) end boron concentration and ARO isothermal temperature coefficient, it can be seen that the calculation results of COSINE software package nuclear design software are in good agreement with the measured data in the low power physical test of AP1000 reactor, and meet the engineering design requirements, with good calculation accuracy.