We propose an optimization design method for actively shielded whole-body open high-field superconducting MRI magnet which accordingly has been simplified to contain only four pairs of superconducting coils. The new design method of open structure superconducting MRI magnet integrates the linear programming algorithm and the genetic algorithm optimization. Through several times of linear programming, and by taking into account the magnetic field, inhomogeneity in DSV, the scope of 5-Gauss fringe field, maximum hoop stress and maximum magnetic field, we can, with the least consumption of lines, get the coils’ initial position and shape, the number of layers of each coil and the number of turns of each layer. And the genetic algorithm was then employed to improve the magnetic field inhomogeneity in DSV to meet the requirements of high-quality imaging. This integrated optimization design method is flexible and effective for designing both open MRI magnet and traditional cylindrical MRI magnet. This paper also illustrates the method for a 1.2 T open MRI magnet optimization design.