Silicon　wafer　thinning　is　mostly　performed　by　self-rotating　grinding　process.　In　grinding,　the　grinding　force　is　a　crucial　factor　of　affecting　the　machining　accuracy　and　surface/subsurface　quality.　In　this　paper,　a　novel　apparatus　and　method　are　developed　to　measure　the　grinding　force　in　silicon　wafer　self-rotating　grinding　process.　Four　thin　film　force　sensors　are　equidistantly　embedded　beneath　the　silicon　wafer　along　radial　direction　and　the　measured　signal　is　transmitted　wirelessly　through　WiFi　protocol.　Based　on　the　proposed　method,　the　normal　grinding　force　and　its　distribution　along　wafer　radial　are　obtained.　The　test　data　indicates　that　the　proposed　approach　is　effective　to　measure　the　grinding　force　with　high　reliability,　high　precision　and　low　cost.