Abstract: Electromagnetic ultrasonic compound energy-field were introduced in the casting and rolling process of AZ61 magnesium alloy strip, and the effects of compound energy field on the microstructure and mechanical property of the alloy were studied. The results show compound energy field could refine grain and homogenize microstructure for AZ61 magnesium alloy strip, and improve the distribution of the second phase on the basis phase, effectively, decrease the mechanical anisotropy of roll-casted strip. Comparing with the ordinary roll-casted magnesium alloy strip, the tensile strength, yield strength, elongation and hardness of the compouond energy field roll-casted magnesium alloy strip were increased obviously, and they were 266.13 MPa, 167.67 MPa, 3.53%, and 79.84 HV, respectively.