This　paper　analyzes　the　general　interaction　of　spinor　field　and　electromagnetic　field,　i.e.　spinor　electrodynamics　with　singular　Lagrangian,　and　the　improved　canonical　quantization　method　of　spinor　electrodynamics　is　given　in　order　to　overcome　the　problems　of　the　second-class　constraint　linear　combination　and　the　first-class　constraint　number　maximization　brought　by　the　traditional　canonical　quantization　method.　In　the　improved　canonical　quantization　method,　there　are　no　problems　of　artificial　linear　combination　and　first-class　constraint　number　maximization,　at　the　same　time,　the　stability　of　the　system　is　considered.　The　improved　canonical　quantization　method　is　more　natural　than　the　traditional　way　and　we　show　that　the　results　of　the　canonical　quantization　of　spinor　electrodynamics　are　equal　to　the　results　of　the　traditional　way.　For　a　general　dynamical　system　with　singular　Lagrangian,　one　can　extendingly　use　the　improved　canonical　quantization　method　to　quantize　the　system.