To improve the speed and accuracy of path synthesis of planar hinge four-bar linkage, a path synthesis method based on B-spline curves was proposed. The method adopted cubic non-uniform B-spline curves to fit coupler curves and used angles between the two adjacent sides of the B-spline curve control polygon as characteristic parameters of coupler curves. Characteristic parameters with dimension parameters of the corresponding four-bar linkage were put into computer to establish an electronic atlas. When a certain number of ordered discrete points were given, a desired curve that passed through these points was constructed by B-spline curve fitting. Characteristic parameters of the desired curve were extracted. Then characteristic parameters of the desired curve with characteristic parameters of the electronic atlas were matched by neural networks to find the four-bar linkage which met the requirements. Ultimately the goal of path synthesis was achieved. Calculation examples show that it can quickly realize path synthesis of four-bar linkage and has high accuracy of path synthesis. And the extracted characteristic parameters have nothing to do with location and scale of coupler curve, reducing the atlas data redundancy.