Abstract: Subquality products often occur in a transient phase during which the level of technological process transfers from one to another if the production is multi-product with small scale. To solve the problem that the transient phase is occurring with the step change in input procedure, a process control approach is designed integration SPC (statistical process control) with EPC (engineering process control) by introducing the system simulation for the manufacturing process comprising the 1st-order dynamic process and the steady-state disturbance ARMA (1, 1). Conventionally SPC and EPC as the means to reduce process fluctuation are quite distinct from each other, while the approach designed integrating SPC and EPC applies ARMA control chart to monitoring the whole manufacturing process with PI controller used to readjust the process. The simulation results showed that the approach is not only able to reduce the fluctuation of process output so as to upgrade the system performance but also potentially advantageous to the cost involved in readjusting it when necessary.