The main helium compressor unit is the core equipment of the high temperature gas cooled reactor project. The unit drives the helium gas flow through the reactor core in the primary circuit of the high temperature gas cooled reactor, and when the reactor starts normally, runs and shuts down the reactor, The helium gas with sufficient flow rate is passed through the primary circuit system, the heat generated by the reactor core is flowing through the steam generator, and the heat is taken away, and then the heat is returned to the reactor core after pressurized by the main helium compressor, which realizes the energy exchange.