A　new　Network　Coding　mechanism　in　WSNs　(Wireless　Sensor　Networks),　which　is　named　COEQ　and　aims　at　balancing　coding　opportunities,　energy　and　QoS,　is　proposed　and　analyzed.　Implemented　on　the　basis　of　traditional　AODV　protocol,　COEQ　evaluates　several　metrics　of　paths　comprehensively　with　TOPSIS　method　including　minimum　remaining　energy,　coding　opportunities,　QoS　and　so　on,　so　as　to　select　the　optimal　transmitting　route.　Experiments　on　NS[2]　show　that　COEQ　can　improve　throughput　and　save　energy　when　the　transmitting　rate　is　low.