Abstract: : This paper investigates the effects of internal and external governance mechanism on annual earnings preannouncement and its characteristics. Using analyst number following to measure the entity’s supervision from outside, and ownership nature, equity restriction degree and earnings management to measure internal efficiency of governance, empirical results show that analyst following promotes the disclosure of annual earnings preannouncement, thus increasing information transparency. The less analyst following is, the later annual earnings preannouncement is disclosed and the more bad news presents. Relative to SOEs, non-SOEs prefer to preannounce yearly earnings, but the precision is lower and good news is predominant. The higher the degree of equity restriction among top five shareholders, the less annual earnings preannouncement is, but when it is disclosed, precision is higher and date is later. We also find that the behavior of annual earnings preannouncement does have continuity. In general, effective external supervision and internal governance mechanism do influence annual earnings preannouncement and its characteristics.