The aim of this research is to explore the mechanism and the suppression methods of creeping phenomenon in hydraulic cylinder system. The nonlinear time-varying laws and function mechanism of hydraulic spring stiffness and friction were revealed through theory analysis. Then, with the nonlinear dynamics methods, the measured dynamic data were thoroughly analyzed. The “jump phenomenon” caused by the nonlinear time-varying characteristic of hydraulic spring stiffness and the “limit cycle oscillation” caused by the nonlinear time-varying characteristic of friction were revealed. The combined effect of nonlinear hydraulic spring force and nonlinear friction is the main cause for the low-speed creeping of hydraulic cylinder. Moreover, the corresponding suppression measures were proposed to improve the low-speed transmission stability of hydraulic cylinder. The results indicate that the research can make the comprehensive analysis of dynamic characteristics of hydraulic cylinder system more realistic.