Abstract: Dramatic changes in the status of the CPR1000 unit’s transient test process will introduce a lot of negative reactivity in a short time. So that the circuit is not easy to maintain a stable core state, and the test process requires accurate adjustment by primary coolant boron concentration to compensate for the reactivity changes. Through research G/R rods changes, power shifts, xenon poisoning variation caused by changes in the reactivity during the test, and based on the current value of the boron concentration and the differential, we analyzed the calculated amount of change in boron concentration and the amount of boron dilution during the test process and provided appropriate controlling strategies of the unit for operating personnel based on the results. Debugging process and test results show that boron dilution accurate analysis can significantly reduce the amount of the unit to control risk, improve the quality of the unit, access to good economic returns.