At present, most of the existing certificateless signcryption schemes proven secure are proposed in the random oracle. Concerning the problem that this kind of schemes usually can not construct the corresponding instance in the practical application, a certificateless signcryption scheme was designed in the standard model. By analyzing several certificateless signcryption schemes in the standard model, it was pointed out that they were all insecure. Based on Aus scheme (AU M H, LIU J K, YUEN T H, et al. Practical hierarchical identity based encryption and signature schemes without random oracles. http://eprint.iacr.org/2006/368.pdf), a new proven secure certificateless signcryption scheme was proposed in the standard model by using bilinear pairing technique of elliptic curves. In the end, it is proved that the scheme satisfies indistinguishability against adaptive chosen ciphertext attack and existential unforgeability against adaptive chosen message and identity attack under the complexity assumptions, such as Decisional Bilinear Diffie-Hellman (DBDH) problem. Therefore, the scheme was secure and reliable.