The traditional cost-based Earned Value Management (EVM) method, and the related Earned Schedule Management (ESM) and Earned Duration Management (EDM), for construction project schedule control has been founded on the basis of the Planned Value (PV). However, the relevant risk factors are usually not taken into account while the scheduler is estimating the duration of an activity. As a result, the de facto PV is far away from the original one when the risk scenarios occur to the activities. To tackle the abovementioned problem, the current research proposes a Risk-based Critical Path Scheduling System (R-CPSS) that assist the scheduler to take into account the spatial and resource constraints as well as the environmental influences when he/she plans the schedule of a project. The proposed R-CPSS is proved to be able to improve the problems of the traditional EVM schedule control methods due to the inaccurate estimation of the PV.