The invention provides a new method for leakage detection of a Freon valve, and belongs to the technical field of valve supervision and inspection. Freon is input via a Freon control vale firstly, high-temperature high-voltage water vapor is input via a high-temperature high-voltage stream control valve then, a mixed gas of the high-temperature high-voltage water vapor and the Freon enters a checked valve, multipoint step-by-step air extraction is performed on the checked valve by using an air extracting device, the extracted mixed gas is cooled in an air cooling device firstly, gas-liquid separation is performed in a gas-liquid separation device subsequently, and, finally, a halogen detector performs detection at air outlet of the gas-liquid separation device. The usage amount of the Freon is reduced, and serious pollution caused by that total fluoride as a working medium performs detection is reduced; a leakage point is accurately located through detection for the tracer gas Freon, and the leakage grade is determined through the number of lit alarm indicating lamps; and the cooling and gas-liquid separation devices are increased, an influence of too high stream temperature is prevented, and inspection precision is improved.