Abstract: The intensity limens for tone bursts with durations of 1 ms,10 mst 100 ms,1000 ms,5000 ms and 10000 ms were measured at different sound pressure levels of 20 dB,30 dB,40 dB,50 dB,60 dB,70 dB,80 dB,90 dB,100 dB.The test paradigm was 2APC,but no ramps were at the beginnings and the ends of testing signals,which were composed through D/A convertor.The data show that variance of Weber fraction △I/I with intensity is distinct from Riesz's result and SPIN theory and that the relations between Weber fraction and intensity for signals of different durations are similar in spite of Weber fraction decreasing to the same with signal duration increasing.This means the difference of pulse measurement of ifitensity limen from Riesz's result and SPIN theory does not arise from the limited signal duration of pulse method and adds new information to hearing research.