The invention belongs to the radiation measurement technical field and relates to a neutron detection method for reducing gamma ray interference by using a GM counter tube.According to the neutron detection method of the invention, when a 6LiI scintillator detector applying a 6LiI scintillator is adopted to detect neutron rays in a mixed radiation field, a first voltage amplitude discrimination threshold is set in the 6LiI scintillator detector; and the signals of low-energy gamma rays detected by the 6LiI scintillator detector are filtered out. In order to eliminate the influence of high-energy gamma rays on a measurement effect, the neutron detection method of the invention includes the following steps that: (S1) a GM counter tube is set near a 6LiI scintillator; (S2) a second voltage amplitude discrimination threshold is set for the GM counter tube; (S3) first signals measured by a 6LiI scintillator detector are recorded, and second signals measured by the GM counter tube are recorded; and (S4) the second signals are multiplied by a correction coefficient, the second signals multiplied by the correction coefficient are subtracted from the first signals, so that a net neutron count rate is obtained.