The invention relates to the technical field of power supply and power transformation, and concretely relates to a gas distribution method of a detector for detecting SF6 gas decomposition products. The method comprises the following steps: 1) vacuumizing the interior of to-be tested electrical equipment; 2) setting the gauge-pressure rated pressure of an SF6 density relay as 0.5 MPa; 3) assembling a sulfur dioxide distributing device; 4) assembling a hydrogen sulfide distributing device; 5) assembling an SF6 pure gas device; 6) calculating the concentration of sulfur dioxide/hydrogen sulfide in the to-be tested electrical equipment; and 7) assembling an SF6 gas decomposition product detector, and reading the gas concentration (mu L/L) of sulfur dioxide and hydrogen sulfide. The method comprises the following beneficial effects that the method is capable of satisfying self detection requirement of the SF6 gas decomposition product detector, enables measurement on the content of sulfur dioxide and hydrogen sulfide decomposed by SF6 gas to be relatively accurate, is capable of timely discovering potential defaults of SF6 electrical equipment and accurately determining the default property, and has important meaning on safe running of the electrical equipment.