It establishes one model with principal-agent theory to motivate the employer in recruiting talent.It supposes that the employee's ability,his effort level and other information of them the employer can't get.The model has two functions: one is that it will help the employer select the employee ability;another is that it can help the employer motivate the employee to work harder.And the paper also explains the model in more visual way with an calculational example.With its corresponding discussion it will help the employer to make decision.