Abstract: An arc voltage feedback PID controller and arc current feedback PID controller with a control algorithm of discrete PID are designed separately to realize optimal control in computer controlling arc spraying system.In order to realize optimization and adaptation of the arc spraying process parameters as well as to reduce blindness in selecting process parameters,a serial communication interface between a PC for spraying data acquisition and a monolithic computer of the control system is designed so that on time modification of the PID control parameters is implemented.At the same time,a genetic algorithm is adopted to optimize the control parameters of PID adjuster,where the difference between the actually sampled value and the setting value of spraying current is made as the judgment criterion to determine the adaptability.The given range of control parameters varies from 0 to 15 and is to be demoted by a coding of four-bit binary string.That is to say,the chromosome code ought to be a 16-bit string.The optimal population of control parameters of the PID adjuster can be obtained through reproduction,crossing and mutation,so that the optimal controlling in arc spraying is realized and to obtain an excellent layer of arc-spraying.