The invention discloses a frost preventing gas inlet system for a high-efficiency gas turbine engine, and relates to a large gas turbine engine. The frost preventing gas inlet system for the high-efficiency gas turbine engine comprises a hollow gas inlet main body; a multi-stage filtering chamber, a dehumidifying chamber, a temperature regulating chamber, a flow speed regulating chamber and an anechoic chamber are formed in the gas inlet main body in sequence from a gas inlet to a gas outlet; a dehumidifier and a humidity sensor are arranged in the dehumidifying chamber; a plurality of stages of heating tubes are arranged in the temperature regulating chamber; the heating temperatures of stages of the heating tubes are risen gradually in the direction from the dehumidifying chamber to the flow speed regulating chamber; a gas flow controller is arranged in the flow speed regulating chamber; the gas flow controller comprises a flow sensor, a regulating valve and a display controller; the flow sensor detects the flow of passed gas and acquires a flow signal; the display controller receives the flow signal of the flow sensor, performs PLC calculation with a set value, and controls the regulating valve to automatically regulate the flow to the set value. The frost preventing gas inlet system for the high-efficiency gas turbine engine remarkably reduces the frosting and icing phenomena of the gas turbine engine in winter operation.