[en] To develop a effective measurement method of radon mitigation efficiency for interior wall paint. By using a local static method, the average radon flux rate of a measured material surface during the period of monitoring can be gotten. The method has been developed using organic glass to make radon cumulation chamber, lint board with a single smooth surface to make samples, PCMR-1 continuous radon monitor and GD-LI gas-through solid radon source. The same measurement conditions can be realized easily and the measurement results can be compared very well. The method can meet the need of radon mitigation efficiency measurement for interior wall paint