For multisource multi-destination wireless sensor networks where the number of source nodes is not equal to the number of destination nodes, a selection cooperation based on packet aggregation is proposed to improve the transmission reliability. Firstly, multi-source multipledestination sensor networks are decomposed into several multi-source single-destination sensor networks by establishing a correlation matrix. Secondly, the packet aggregation strategy is implemented for multi-source single-destination networks. Thirdly, considering the impact of transmission sequence on each source node, three scheduling methods are introduced into the selection cooperation. Finally, three relay selection strategies are presented to facilitate multi-objective optimization under the premise of guaranteeing system transmission reliability. Simulation results show that the proposed method can not only improve the transmission reliability of the system, but also satisfy different network requirements.