Taking A-share listed companies in China from 2007 to 2015 as a sample，this paper studies the impact of auditor experience on audit delay. The result show that：（1）With the growth of auditor experience, audit delay decreases and audit efficiency improves, which supports the theory of “Learning by Doing”. （2）The role of auditor experience on reducing audit delay only exists in the company where auditor rotates. （3）Furthermore，client size and auditor size play a mediate role between auditor experience and audit delay in the sample of auditor rotation. Specifically，in the big client and non-big10，the effect of auditor experience on audit delay is more significant.（4）In addition，the effect of auditor experience on audit delay is mainly reflected in the review auditor. This paper studies the influencing factors of audit delay from the perspective of auditor，which helps the supervisory and accounting firms understand the importance of improving auditor experience.