Abstract: Symmetric encryption algorithm can not solve the security problems effectively existing in the wireless sensor networks. This paper proposes a key distribution scheme based on symmetric encryption algorithm and elliptical encryption algorithm,which is optimized by asymmetric encryption algorithm and utilizes communication path created by symmetric polynomials and authenticate used by elliptical encryption algorithm,and which can bring shorter session key after the mutual authentication between nodes.This work analyses connectivity of the allocation scheme by the random graph theory and we proved the scheme has very high security in the practical application which is based on the research of the enemy attack process,The scheme proves feasibility and security based on the scheme detailed analysis and comparison.