Abstract: To address the issues of tooth surface wear in non-circular gear transmission, which result in increased meshing backlash and reduced transmission accuracy, a solution for constructing variable tooth non-circular gears was proposed. Based on the principle of side clearance adjustment and structural form of variable tooth thickness gear teeth, a multi-layer envelope model was created based on the non-circular gear pitch curve. The tooth profile curves of each section were extracted through image processing and then swept to form a three-dimensional digital model of the variable tooth non-circular gear, which was processed using multi-axis electric discharge wire cutting. A test bench was built for meshing testing. The experimental results demonstrate that the variable tooth non-circular gear pair operates smoothly with no interference. By adjusting the relative axial position between the driving gear and the driven gear, the meshing backlash can be adjusted. The angular velocity curve output by the driven gear aligns with the expected motion law. The variable tooth non-circular gear is advantageous for precision transmission under variable speed conditions and holds significant promotion value.