The combination of computer and PLC was adopted in the explosive melting machine measuring and controlling system. The system was composed of computer monitor system, PLC control system, apparatus and meter system, power and vacuum assistant system. The computer, PLC and spot instrument were combined by industrial control net. Thus centralized management, monitor, dispersive management and units management were realized. The absolute encoder was adopted, so the rotate speed and position of the machine could be measured in real time. The machine could be operated manually or automatically, Human-machine intercommunion was all right and all the operation of the machine could be performed on the computer.