The　application　of　automatic　code　generation　technology　improves　the　efficiency　and　quality　of　software　development.　But　generating　business　logic　automatically　is　an　urgent　problem　in　code　generation　fields.　This　article　analyzes　the　underlying　business　logic　components　specifically　and　points　out　the　reasons　for　the　business　logic　generated　difficultly.　Then　abstract　the　model　of　the　part　for　which　the　business　rules　based　on　production　rules,　and　designs　and　implements　the　code　generator　based　on　the　production　system　principles,　so　that　code　of　business　logic　generated　automatically.　©　2012　IEEE.