In　order　to　enhance　the　anti-jamming　capability　of　simultaneous　transmit　and　receive　based　cognitive　anti-jamming　(SCAJ)　communication　system　in　the　complex　electromagnetic　environment,　an　improved　spectrum　sensing　scheme　based　on　energy　detection　(IED)　is　proposed　in　this　paper.　For　the　SCAJ　receiver　using　the　IED　scheme,　the　closed　expression　of　jamming　detection　and　false　alarm　probability　under　Rayleigh　fading　channels　is　derived,　and　the　outage　probability　of　SCAJ　system　is　analyzed.　Simulation　results　show　that　the　effect　impacted　by　selfinterference　(SI)　at　SCAJ　receiver　can　be　suppressed　and　the　outage　performance　of　SCAJ　system　is　improved　by　the　proposed　IED　scheme.　©　2016　ACM.