1. A method for reconstruction of magnetic resonance imaging comprising the steps of: collecting data in each initial channel and filling said data in an initial K-space, said data including data in a calibration data area and data in an undersampled area; constructing a target virtual space Sp, and mapping initial K-space data to said target virtual space Sp; constructing, in said target virtual space Sp, a target optimized virtual space Sp 1 by retaining channel data having a high signal-to-noise ratio; filling out said undersampled area in said target optimized virtual space Sp 1 and acquiring complete data in said target optimized virtual space Sp 1 ; converting said complete data in the target optimized virtual space Sp 1 to an image domain to obtain an image.