In the full length core drilling in well Qiansuidi-1 of southern China, the winch sensor installation was realized by processing the simulation winch, the suspended load sensor was replaced by the installation of a switch and the pump punching sensor was installed on the pulley protection cover, which made the gas logging being smoothly carried out. The main factors affecting the gas logging results in well Qiansuidi-1 are the reservoir, drilling fluid, drilling engineering and degasser. In order to reduce the misunderstanding of gas logging data, it is necessary to strengthen the training of logging personnel on site to effectively eliminate the influence led by controllable factors on gas logging and improve the the accuracy of geological drilling gas logging to a certain extent to provide powerful data support for the division of shale gas formations in south China.