In Mobile Ad hoc network (Manet), to solve the problems of the message receiver privacy exposure and signcryption (decryption) unfairness in existing signcryption schemes, a new ID- based multi-receiver signcryption scheme based on bilinear pairings is proposed. We also analyzed its security and efficiency. The result shows that the new scheme is provable secure in the random oracle model. It is significantly efficient and with low computation cost and is very suitable for secure communication in Manet. Then, the scheme can avoid the destruction of the malicious nodes. This scheme can satisfy the requirement of security and efficiency in real network environment, it is more propitious to applications in practice.