The invention belongs to the technical field, and in particular, relates to a method for calculation of boron concentration limiting value for ensuring that a moderator temperature coefficient is negative when the moderator temperature coefficient is positive during nuclear power plant zero power physical testing. The method includes the following steps: step one, the moderator temperature coefficient MTC under a total loss critical boron concentration of a control rod with zero power at the beginning of life period in a nuclear power station is obtained; step two, if the MTC is not positive,calculation of the boron concentration limit value is not carried out, and the method is ended; if the MTC is positive, the critical boron concentration CB in the test state in the step one is recorded; step three, the boron concentration limiting value is determined through a calculation formula of CB(limit value)=CB-50*MTC; and step four, when the boron concentration of a reactor core is determined not to exceed the CB (limit value), the MTC is ensured to be negative. The method has a wide range of application, and the calculation formula can be applied to different cycles of different typesof reactors, and is independent of a loading mode of units.