An MRI system for imaging a moving subject is provided. The MRI system includes a magnet assembly and an MRI controller. The magnet assembly is configured to acquire a k-space via scanning the subject. The acquired k-space includes a plurality of datum each having a motion error. The MRI controller is configured to receive the acquired k-space from the magnet assembly. The MRI controller is further configured to suppress the motion error of each datum by reconstructing the k-space via a soft gating threshold in a non-iterative manner.