As one of the important forms of macroeconomic environment, business environment affects many aspects of micro-enterprises' financial behavior, but the research on its impact on major shareholders' tunneling and mechanism testing is still insufficient. Therefore, this paper takes A-share listed companies in China's capital market from 2008 to 2018 as research samples to empirically examine the impact of business environment on major shareholders' tunneling. The results show that:there is a significant negative correlation between business environment and major shareholders' tunneling, indicating that optimizing business environment is conducive to restraining major shareholders' tunneling; compared with non-state-owned enterprises, the restraining effect of business environment on major shareholders' tunneling is more obvious in state-owned enterprises; further testing of impact mechanism reveals that optimizing business environment can improve internal control quality, audit quality, and corporate information transparency, which constitutes the main influence path of business environment restraining major shareholders' tunneling. The above conclusion enriches literature research on economic consequences of optimizing business environment, clarifies the mechanism of business environment affecting major shareholders' tunneling behaviors, and provides direct empirical evidence for improving and optimizing business environment.