In order to study the dynamic contact performance of cylindrical gear with variational hyperbola and circular-arc-tooth-trace,based on the tooth surface equation obtained from the machining principle of rotary cutter,a precise 3 D model of gear can be established by using MATLAB and UG. The distribution of contact stress in the gear tooth surface during the meshing process is obtained by ANSYS LS-DYNA. By studying the dynamic contact performance of cylindrical gear with variational hyperbola and circular-arc-tooth-trace under different radius of the tooth line,the influence of the radius of the tooth line on the meshing performance of the gear is obtained. By studying the dynamic contact characteristics of cylindrical gear with variational hyperbola and circular-arc-tooth-trace under different pressure angles,the influence of pressure angle on the dynamic meshing characteristics of the gear is obtained. By studying the dynamic contact stress of the gear under different loads,the influence of load on the dynamic meshing characteristics of the gear is obtained. The analysis results provide reference for the design and engineering application of cylindrical gear with variational hyperbola and circular-arc-tooth-trace.