Abstract：The paper mainly deals with the sampling methods and gas and mud analytic procedure in the field lab of the Chinese Continental Scientific Drilling project (CCSD). The use of the degassing equipment and anomalous gas collecting equipment and their influence on the results of gas analysis are described, and the accuracy and precision of gas analysis are compared. Four different methods of on-site mud sample treatment, especially the last two methods, are discussed. The influences of different factors, such as the accuracy and precision, duration of placement of clear fluids in the upper layer and duration of mud treatment are compared.