Objective:In order to solve the problem of poor stability, high cost and small gas flow of ternary gas mixing equipment.Methods:A ternary gas mixing system based on the ideal gas law and Dalton?s law of partial pressure was proposed, and the system calculated errors and adjusted parameters by the designed algorithm, and adopted the connection of cylinder, sensor and so on.Results:After adjusting the mixing according to the relative deviation, the average relative deviation of the gas concentration of CO2and O2was 0.86% and 0.75% respectively, and the gas concentration accuracy met the technical requirements of ＜1%, and the high-precision gas mixing of the ternary gas can be better achieved.Conclusion:The system can realize rapid and stepless regulation of ternary gas, and high-precision continuous mixing.