The invention is applicable to the technical fields of reactor control and protection systems, and provides an experimental treatment method, device and system for an instrument system detector of a pressurized water reactor power plant. The method comprises the following steps: collecting indicator data of the detector; amplifying and regulating the indicator data; performing calculating processing on the amplified and regulated indicator data, so as to obtain experimental data; evaluating the performances of the detector according to the experimental data. Through the method, the technical problem that the performances of the detector cannot be tested and verified in advance is solved, off-line machine testing for a certain time to the detector is realized, and the reliability of the quality and performances of the detector are guaranteed.