The traditional models of evaluating human resources are mainly based upon the discounted value of future payment, but these models fail to take the employment risk into account, and often neglect the uncertainty and underes- timate the human resource value. This paper first introduces the option theory, and then presents human resources as the real commodity for the call option. Second, concerning the choices for the uncertainty decision, the decisions of delay- ing the employment of the human resources, expanding or deducing the scale of human resources, giving up or chang- ing human resources, etc., are made to deal with the future uncertainties appropriately. This will cause the investment to be more beneficial or to reduce the loss. Finally, the expand option theory of real options is used to evaluate the value of reinvestment in human resources, and the expand option theory could be provided as a reference for management im- plementation and decision-making in human resources. The traditional models of evaluating human resources are mainly based upon the discounted value of future payment, but these models fail to take the employment risk into account, and often neglect the uncertainty and underes- timate the human resource value. This paper first introduces the option theory, and then presents human resources as the real commodity for the call option. second, concerning the choices for the uncertainty decision, the decisions of delay- ing the employment of the human resources, expanding or deducing the scale of human resources, giving up This will cause the investment to be more beneficial or to reduce the loss. Finally, the expand option theory of real options is used to evaluate the value of reinvestment in human resources, and the expand option theory could be provided as a reference for management im- plementation and decision-making in human resources.