A method of determining effective coil units of a radio frequency, RF, coil for imaging a field of view, FOV, to be scanned using a magnetic resonance imaging, MRI, system, wherein the FOV to be scanned is a region to be imaged of a subject, wherein the RF coil of the MRI system includes a plurality of coil units (A1, A2,... F8) which are arranged such that a subset of the coil units covers the FOV to be scanned, the method comprising: adjusting, by moving the subject, a center of the FOV to be scanned to a magnetic field center of the MRI system based on an initial scanned image of the subject; determining coordinate values in a coordinate system for each of shape-characteristic points (P1, P2, P3, P4) of the FOV, wherein the origin of the coordinate system is located at the magnetic field center of the MRI system, and the shape-characteristic points indicate a shape of the FOV to be scanned; applying a preset gradient magnetic field to the FOV in addition to the magnetic field of the MRI system, thereby forming a superimposed magnetic field having a superimposed magnetic field intensity; determining coil units respectively covering the shape-characteristic points according to a gyromagnetic ratio coefficient of hydrogen atoms and the superimposed magnetic field intensity at each of the shape-characteristic points, obtaining an effective region by connecting the determined coil units according to the shape of the FOV; and determining a coil unit located in the effective region as an effective coil unit to be activated for imaging the FOV by the MRI system; wherein the step of determining coil units respectively covering the shape-characteristic points according to the gyromagnetic ratio coefficient of hydrogen atoms and the superimposed magnetic field intensity at each of the shape-characteristic points comprises, for each of the shape-characteristic points: obtaining a target resonance frequency for the shape-characteristic point according to the gyromagnetic ratio coefficient of hydrogen atoms and the superimposed magnetic field intensity at the shape-characteristic point, wherein the target resonance frequency is a resonance frequency of hydrogen atoms at the shape-characteristic point; exciting hydrogen atoms at the shape-characteristic point by taking the target resonance frequency for the shape-characteristic point as excitation frequency; and determining a coil unit which acquires a strongest signal during the excitation for the shape-characteristic point as the coil unit covering the shape-characteristic point. adjusting, by moving the subject, a center of the FOV to be scanned to a magnetic field center of the MRI system based on an initial scanned image of the subject; determining coordinate values in a coordinate system for each of shape-characteristic points (P1, P2, P3, P4) of the FOV, wherein the origin of the coordinate system is located at the magnetic field center of the MRI system, and the shape-characteristic points indicate a shape of the FOV to be scanned; applying a preset gradient magnetic field to the FOV in addition to the magnetic field of the MRI system, thereby forming a superimposed magnetic field having a superimposed magnetic field intensity; determining coil units respectively covering the shape-characteristic points according to a gyromagnetic ratio coefficient of hydrogen atoms and the superimposed magnetic field intensity at each of the shape-characteristic points, obtaining an effective region by connecting the determined coil units according to the shape of the FOV; and determining a coil unit located in the effective region as an effective coil unit to be activated for imaging the FOV by the MRI system; wherein the step of determining coil units respectively covering the shape-characteristic points according to the gyromagnetic ratio coefficient of hydrogen atoms and the superimposed magnetic field intensity at each of the shape-characteristic points comprises, for each of the shape-characteristic points: obtaining a target resonance frequency for the shape-characteristic point according to the gyromagnetic ratio coefficient of hydrogen atoms and the superimposed magnetic field intensity at the shape-characteristic point, wherein the target resonance frequency is a resonance frequency of hydrogen atoms at the shape-characteristic point; exciting hydrogen atoms at the shape-characteristic point by taking the target resonance frequency for the shape-characteristic point as excitation frequency; and determining a coil unit which acquires a strongest signal during the excitation for the shape-characteristic point as the coil unit covering the shape-characteristic point.