With development of outsourcing computation, it is possible for clients with limited computing resources to outsource heavy computational tasks to the cloud server and thus relieve huge burden of the client. As continuous attention of delegation in recent years, requirements of security and efficiency are badly concerned undoubtedly, especially for matrix multiplication. Considering wide applications of matrix multiplication, e.g. graph processing and large date processing, in this paper, we present an identity-based publicly verifiable delegation scheme in amortized model which meets the need of security and efficiency both. Moreover, by using an secure encryption algorithm and a verification certification, the security analysis of the proposed scheme demonstrates the privacy of matrixes involved and the correctness. To demonstrate efficient properties, we compared our scheme with some existing works in terms of functionality as well as computation, storage and communication overhead.