Human resources risks lead to undermine project performance, however, due to complex and flexible characteristic of the human resources risks, the prediction and control of risks resulting from human resources is more difficult than other risk factors. In order to achieve effectively construction goal, based on the generalized project risk element transmission theory and system dynamics, a system dynamics model of human resources risk element transmission during construction projects was developed, which analyzed different influence results that human resources risks of different time and different level caused and dynamic transfer process of human resources risk elements. Firstly, the restoration process of human resources can significantly delay project duration after human resources risk occurrence. Secondly, in the run of project construction, asymmetric composition of human resources can create unsaturation of real workload, which caused inefficiency of human resources. Finally, during different time that human resources occur, different measures which employed either increase numbers of human resources to speed up construction or no increase human resources result in delay of project duration will seriously influence project cost. Moreover, the case study makes a more particular knowledge of human resources risk elements transmission to quantitative description of project duration and cost. This model can provide important information for risk managers and project managers addressing human resources risk.