In　order　to　investigate　the　problems　of　complex　contour　description　and　complex　quantitative　relationship　between　cam-type　switching　mechanism　contours　and　force　value　curves,　a　design　method　of　cam　contour　was　suggested　based　on　B-spline　and　energy　theory.　The　descriptive　and　the　differential　equations　of　B-spline　were　given,　the　quantitative　relationship　equation　between　the　internal　potential　energy　and　external　work　of　switching　mechanism　was　established,　and　the　iterative　design　algorithm　of　mechanism　contours　was　presented.　A　cam-type　wiper　switch　contour　was　designed　by　using　MATLAB　and　the　suggested　cam　contour　design　method,　which　involved　the　energetic　relationship　equation　and　the　iterative　algorithm.　The　design　results　indicate　that　the　derived　contour　may　satisfy　the　expected　force　value　curve　requirements,　and　the　derived　force　value　curves　by　using　B-spline　are　more　effective　in　improving　the　contour　precision　and　the　switch　performance　than　that　by　using　high-order　polynomial　fitting　curves.　©　2017,　China　Mechanical　Engineering　Magazine　Office.　All　right　reserved.