Under the multi-echelon repair and supply system， spares supply with lateral transshipments is an effective approach to improve support effectiveness. Focus on this issue， according to theories of life-death process and mutil-ehcelon technique for recoverable item control （METRIC）， spares lateral transshipments model under multi-echelon multi-indenture system is built， and heuristic algorithm is introduced to get the model result. Take the equipment availability as constraint and spares cost as objective， the spares inventory is optimized by marginal algorithm. Through the given case， the model correctness is verified by simulation， compared with the result without transshipments， numerical studies show that our model is superior in improving the support effectiveness of equipment.