The utility model belongs to the technical field of engines, and relates to a temperature-variable air intake system of a gasoline engine. An exhaust air inlet and an exhaust air outlet of an air-to-air heat exchanger are connected with the upper end of the engine and an inlet of an air exhaust pipe; a fresh air inlet and a fresh air outlet of the air-to-air heat exchanger are connected with an outlet of an air filter and an inlet of an engine air intake manifold; the outlet end of an air intake pipe II is serially connected with a throttle valve I; another outlet of the air filter is connected with an inlet of an air intake pipe III, the air intake pipe III is connected with a throttle valve II and an intercooler serially in sequence, and an electronic water pump is serially connected in a water intake pipe of the intercooler; an air flow meter is connected on the engine air intake manifold in series; an outlet of the engine air intake manifold is connected with the lower end of the engine; a temperature sensor is fixedly connected on the engine air intake manifold; an inlet of the engine air intake manifold is connected with an outlet of the air intake pipe III and an outlet of the air intake pipe II. The intake air temperature of the gasoline engine is adjustable, fuel economy of partial load of the gasoline engine is improved, waste heat of part of exhaust air exhausted by the gasoline engine can be recycled, and energy waste is reduced.