Investigation on the creep property of coal containing gas is an effective means for understanding the mechanism of delay outburst of coal and gas in a coal mine. This paper conducts triaxial creep tests on the specimens of gascontaining coal using a selfmade creep experimental apparatus to determine the creep law for coal containing gas. An improved triaxial creep model is developed for containing gas by coupling a Nishihara model with another viscoelastoplastic body which can describe the deformation property of nonNewtonian fluids. The parameter fittings are conducted based on the experimental dada.The present model is examined in terms to the results of triaxial creep tests in various stresslevel cases. The result shows that the proposed model for gascontaining coal can properly represent the creep deformation at different creep stages, especially at the accelerating stage. The instability condition of the model for coal containing gas is also discussed according to stability theories of differential equation solution.