The effect of rolling temperature on microstructure evolution and mechanical/thermal properties of Mg-4Zn-1Mn-1.2Ce alloy was investigated. Results indicate that Mg-Zn-Ce (τ phase) second phase and α-Mn were crushed and distributed along the rolling direction in the as hot-rolled Mg-4Zn-1Mn-1.2Ce alloy. When the rolling temperature was lower than 400^oC, most grains became deformed grains, but the proportion of recrystallized grains increased due to the occurred static recrystallization during heat preservation in the intervals between rolling-passes when the plate was rolled at 425^oC. The tensile strength, yield strength and elongation of the rolled Mg-4Zn-1Mn-1.2Ce alloy sheet were 386 MPa, 356 MPa and 4.8%, respectively, as well as the thermal conductivity of 127.3 W·(m·K)^-1 when it was hot-rolled at 375^oC. Annealing has resulted in a slight decrease in strength, but a great improvement in toughness. In the case of the alloy rolled at 375^oC, its elongation increased from 4.8% to 23.5% after annealed at 400^oC/60 min. Also, the thermal conductivity of the annealed alloy decreased about 4~9 W·(m·K)^-1 in comparison with that of the as-rolled one.