According to the demand and development trend of industrial production,a set of powder additive manufacturing control system based on PTA（Plasma Transferred Arc） is designed and built. The system is divided into two parts:heat source control and motion control. In the heat source control part,PLC is used as the control core,and the time sequence control of the heat source component is realized by combining with the touch screen of Winton,and the parameter setting module is designed. By adding subroutines, the switching between the two control modes of heat source can be realized,and the time intervals of the two control modes can be set in the touch screen. In the motion control part,Arduino MEGA 2560 motion control card is used as the control core. Through modeling and layered generation of welding gun motion G code,the G code is compiled into the pulse signal of stepping motor driver,which drives the stepping motor on the three-axis sliding table to rotate and realize the three-dimensional motion of plasma welding gun. The connection between heat source and motion is established by rotary encoder to realize the integrated control of additive manufacturing process. Finally,the feasibility and reliability of the additive manufacturing process control system are verified by process test.