In　this　paper,　the　improved　canonical　quantization　method　of　the　self　dual　field　is　given　in　order　to　overcome　linear　combination　problem　about　the　second　class　constraint　and　the　first　class　constraint　number　maximization　problem　in　the　Dirac　method.　In　the　improved　canonical　quantization　method,　there　are　no　artificial　linear　combination　and　the　first　class　constraint　number　maximization　problems,　at　the　same　time,　the　stability　of　the　system　is　considered.　Therefore,　the　improved　canonical　quantization　method　is　more　natural　and　easier　accepted　by　people　than　the　usual　Dirac　method.　We　use　the　improved　canonical　quantization　method　to　realize　the　canonical　quantization　of　the　self　dual　field,　which　has　relation　with　string　theory　successfully　and　the　results　are　equal　to　the　results　by　using　the　Dirac　method.