The utility model relates to a semiconductor device gas mixing controller. The following technical scheme is adopted: the semiconductor device gas mixing controller comprises an input portion, a control processing portion, an output portion, RS485 communication ports and a power supply. The input portion comprises an analog signal acquisition module, a hydrogen and oxygen ratio input module and a SIH4 pressure input module. The output portion comprises an analog channel output module, a control channel output module, a hydrogen and oxygen ratio protection output module and a SIH4 overpressure output module. One RS485 communication port is connected with digital mass flowmeters, and the other RS485 communication port is connected with an upper computer. The power supply adopts an isolation DC-DC module, wherein the power supply is converted into five loops through the isolation DC-DC module to supply power required by the gas mass flowmeters, the analog channel chip, a single chip microcomputer system, the master communication port and the slave communication port. The controller of the utility model can be used to monitor the gas flow of different mass flowmeters according to the control rule and the program of the upper computer on each gas, and the interlocking operation and the protection operation are performed at the same time, so the controller is applicable in gas analog mass flowmeters or digital mass flowmeters, and the controller can be connected with eight mass flowmeters, so that the controller is especially applicable in a semiconductor device having a gas controller portion, and advantages of high intelligence, strong functions, low cost, high accuracy, security and reliability can be realized.