A novel doubleringplate gear reducer (DRPGR) is designed and its experimental validation is conducted. By using the closedgraph method, the modification coefficients of internal gearing in DRPGR are determined. Based on this, the overall structure of the reducer is designed and its kinematics simulation is achieved. With APDL programming language of ANSYS, a 3D finite element (FE) model of DRPGR is established, and its modal analysis and loaded tooth contact analysis (LTCA) are conducted respectively. The modal analysis reveals that the lower natural frequencies of DRPGR are much higher than the input frequency and the lower modes can be classified as vertical and horizontal bending of input and output shafts. The LTCA indicates that three pairs of gear teeth contact simultaneously at rated output torque. Due to the multiteeth contacts, the maximum stress is much lower than the permissible stress of internal gearings. The experimental tests of the prototype validate that DRPGR is adapted to both singledriven and dualdriven work condition. When singledroved, DRPGR can eliminate the kinematic uncertainty by non180degree phase difference design. DRPGR claims a better dynamic performance in dualdriven work condition. The efficiency of DRPGR increases with the increment of output torque and the reducer has an excellent shortterm overloaded capacity. The experimental results validate that the proposed method can be used to guide the design of that kind of reducer.