Multivariate cryptography possesses the characteristic of high efficiency as well as resistance of quantum attack, which makes it become one of the main candidates of being possible alternative to conditional public cryptography in post-quantum ear.Multi-layer Matsumoto-Imai (MMI) scheme was proposed by Jiao Luyao in 2013 which improved the original MI scheme,and its construct of central mapping of multi-layer has made it safer than MI without changing the advantage of high efficiency.Combined MMI with CyclicRainbow proposed by Petzoldt, a signcryption scheme is put forwarded through modifying MMI scheme with the idea of constructing the central mapping in Hidden Field Equation (HFE).In this passage, compared to the original MMI scheme, our scheme is safer than before and layering attack is not available any more.Besides, the key size of signcryption is smaller than MMI after modification, and it also have encryption and signature been done simultaneously.