Constructions sites are affected by Diversity workplace, complexity of construction, Change of place, Mobility of workers and so on. In a single establishment, Prime contractors and subcontractors have to conduct their work at the same time. There are a lot of unpredictable risks when the construction is running, coordination between contractors is very important to do a risk assessment under the condition. Large Construction companies were investigated by previous studies. Survey research is applied to the risk assessment. In the writing, Risk assessment of the entire lower level. Because of the low level of risk factors to find. Also, There was a limit to investigate accidents. Confirmed that Effort to derive a risk factors were desperately of the risk assessment. Results were obtained through previous studies. The PCM is several experts should be joined. Experts Site Manager, Supervisor, Safety Manager, Director Contractor, Work team leader is required to participate. Construction plans, Process Planning to the risk find beforehand. And Determines how the operations and the control. Also, Made it into the database. and PCRA can be used in the risk assessment was developed.