This paper examines that the investors do not ignore but overestimate the earnings persistence, which rejects the earnings persistence hypothesis for the post earnings-announcement drift. Investors have more concerns about the past accounting information than the current accounting information probably because of the conservatism in the information uncertainty. Investors are not able to distinguish the influence on the unexpected earnings persistence from the conditional accounting conservatism in short period, which decrease the current unexpected earnings and the uncertainty from the current unexpected earnings to reduce the risk premium, while investors are not able to distinguish the influence on the unexpected earnings from the unconditional accounting conservatism in long period, which increase the current unexpected earnings and the uncertainty from the current unexpected earnings to enlarge the risk premium.