Abstract: This paper investigates the effects of explosion depth and water-level on the time delay based on the experiments carried out at Jiemian reservoir in Sanming of Fujian by Fujian Earthquake Agency in November of 2014. Analyses on the data from the station YXBM show that under the same water level, pressure pulses are affected by air-gun explosion depth so little that the correlation coefficient is high and the time delay is low, while those of the bubble pulses are significantly different. They arrive faster as the explosion depth increases. The arrival time of bubble pulses advances nearly 80 ms when the explosion depth changes from 8 m to 30 m, which is quite consistent with the records of the ocean bottom seismometer. The time delay is related to the decreasing of the period of signals resulted from the explosion depth increasing. Both of the pressure pulses and bubble pulses are similar while stimulated at the same explosion depth of air-gun under different water levels. So the explosion depth should be considered in the future study of exploring and monitoring the subsurface structure and its temporal variations using air-gun active source.