Mg/Al laminated composite was prepared by hot rolling with the self-developed cross-corrugated roll. The tensile strength in TD and RD were tested, and the effects of annealing time on microstructure and mechanical properties were studied. The results indicate that inter- metallic compounds (IMCs) are generated at bonding interface under the condition that the total reduction ratio is 37.5%, annealing temperature is 250 ℃, while the annealing time is 2 h and 4 h, respectively. There is Mg2Al3 phase near 5052 and Mg17Al12 phase near AZ31B, and the thickness of IMC layer increases with the increase of annealing time. After annealing, the TD tensile strength of laminated composite decreases from 309.33 to 276.06 MPa, the RD tensile strength decreases from 302.09 to 274.21 MPa, but the elongation in TD direction increases from 5.25% to 23.24%, and the elongation in RD direction increases from 3.05% to 22.74%. With the increase of annealing time, the elongation becomes stable. This study provides an experimental and technical reference for the preparation of Mg/Al laminated composite with high performance.