The　relationship　between　the　performance　cost　and　the　processor　utilize　of　the　real-time　control　tasks　in　different　control　phase　was　investigated,　further　more,　a　feedback　scheduling　system　based　on　linear　assignment　algorithm　was　constructed,　and　in　this　system,　processor　utilize　was　assigned　by　feedback　scheduler　according　to　the　control　error,　that　is,　real-time　control　tasks　would　get　more　processor　utilize　when　its　control　error　increases.　Simulation　results　verified　that　the　feedback　scheduling　system　based　on　control　error　can　improve　the　overall　systems　performance　under　limited　computing　resources.