A wireless sensor network (WSN) typically operates in an unreliable wireless environment with power restrictions. Many researchers are primarily interested in the energy awareness and communication reliability of WSN to maximize the useful life of the network. However, addressing the conflicting issues of improving energy efficiency and fault tolerance simultaneously is a difficult task. Most of the previous studies have shown that both problems can be addressed through the use of data link or network layer protocols. In this article, we present a cross-layer protocol, which integrates a multi path routing protocol and a data interleaving technique based on the Reed-Solomon code. We formulate the problem of selecting the transmission paths of the sensor as a problem of the backpack and solve it by a greedy algorithm. Our multi path routing protocol allows each sensor to select multiple transmission paths using the proposed optimization algorithm. Based on multiple transmission paths, the data collation technique is employed using Reed-Solomon code to provide reliable data transmission. The results of the simulation demonstrate that our scheme outperforms existing multi path routing protocols with respect to the network life span, since it balances the energy consumption and promotes the reliability of the communication.