Abstract: Batang fault constitutes a critical segment of the western boundary fault of Sichuan-Yunnan rhombic block, and its activity has attracted significant attention. Soil radon gas measurement has been widely used in the reconnaissance survey of active faults. Huangcaoping area, crossed by Batang fault, was taken as the research object, and the means of field geological survey, soil radon gas measurement and UAV mapping were used to discriminate 5 secondary faults and seismic ground fissure in the study area. Fault F₁ and the surface rupture S₁, S₂ are small in development scale, shallow in burial depth, and steep in occurence. Fault f₁ is in small scale, dipping to the southeast with a high dip. Fault f₂ is a medium scale fault with a slightly gentle dip, dipping to the northwest, which is speculated to be the eastern boundary of Batang fault. The radon gas measurement anomaly corresponded well to the distribution characteristics of the faults in Batang fault, and the radon gas measurement method could determine the position of hidden faults in Batang fault more quickly and effectively. This method could provide references for the next step of fault activity research and historical earthquake research.