Human behavior is one kind of complicated phenomena. Comprehensive and profound understanding of their behavioral characteristics has been the direction of the tireless efforts of people. In recent years, studies have shown that: if the time series of human behavior is a Poisson process, its probability distribution is exponential distribution interval. However, currently a number of empirical analyses show that: some of the probability distribution of the interval of events triggered by human behavior are Power-law distribution and the process is an intermittency process. In this paper, based on a statistical analysis of about 1300000 user log of TJU-ACM from 2004 to 2013, we found that distribution of the interval of submit time of users follows a power law with an exponent characteristic, which is a difference from the analysis results of the previous wording. After investigation, we knew the reason for this result is that the answer to the question of ACM online is driven by a specific interaction of interest. It also further demonstrates that for the time series of some natural phenomena and human behavior, its time domain features are shown a strong episodic, and its distribution characteristics are driven by specific factors.