Abstract: The polyimide standard material (with certificate) was used as the experimental sample, and the effects of laser voltage, pulse width, and sampling time on the thermal diffusion coeffcient measurement of polyimide were studied within the temperature range of 25~250 ℃. The results showed that when the laser voltage was greater than or equal to 260 V, the pulse width was greater than or equal to 500 μs, and the time range was 8~12 times the half heating time, the deviation of the detection results in the temperature range of 25~200 ℃ was within 5% of the standard value, indicating that high accuracy and good repeatability of the experimental conditions. When testing the thermal diffusion coeffcient of polymer materials with low thermal diffusion coeffcient by laser flash method, the laser voltage and pulse width should be increased to increase the total energy of the laser input sample, in order to reduce the effect of heat loss during the heat transfer process and obtain accurate and stable results, which provides a reference and guidance for experimental parameter settings of accurately measuring the thermal diffusion coeffcient of polymer materials with laser flash method for researchers.