This paper applies the model of reputation mechanism into analysis of the informational mechanism and incentive scheme of Primacy Effect.It is shown that under the condition of time-invariant ability,early performance has permanent influence on the form of impression,while the incentive effect decreases as time goes on.Furthermore,when the ability follows self-regression process,the agent's labor supply will be improved on in the stationary level.The conclusion of this paper formally approves the description of Primacy Effect,such as it's deteriorating incentive effect in long-term view,the combination of Primacy Effect and recent performance will work more effectively,which shed light on management practice.