Abstract: The measuring range of single detector wide range dosimeter can be more than eight orders of magnitude, far greater than the conventional dosimeter with pulse counting method. The calculation error of average wait time directly affects the accuracy of the final radiation intensity or dose rate in the dosimeter. The essence of obtaining average time is processing wait time by low-pass filter. In signal process domain, digital filter design method is based on the signal spectrum analysis. It doesn’t consider the random factors of nuclear detection. Therefore the filter designed by the tool cannot improve the two indicators of response speed and measurement accuracy, simultaneously. Aimed at the characters of wait time measure in single detector wide range dosimeter and digital filter design, a new filter design method based on multi-objective particle swarm optimization was proposed. In order to verify the performance of the method, the filter designed by filter design tool was compared with that by this method. Theoretical analysis and experimental results show that compared with the filter designed by conventional method, the filter designed by this method is the fastest response speed under the same conditions of measurement accuracy, and is also the highest measurement accuracy under the same conditions of the response speed. This method is applicable to design digital filter of wide range dosimeter and other types of radiation detection devices.