The invention discloses a magnetic liquid sealing device with radial isodirectional magnetization of permanent magnets, belongs to the field of mechanical engineering sealing and solves the problem that under the working condition with smaller axial size, the traditional magnetic liquid rotary sealing device cannot use a sufficient amount of the permanent magnets and pole shoes due to size limitation to cause the pressure endurance capability of the magnetic liquid sealing device not to be sufficient, thus sealing fails. The magnetic liquid sealing device with radial isodirectional magnetization of the permanent magnets comprises the permanent magnets which are radially magnetized in the same direction, the pole shoes, magnetism isolation positioning rings and the like. According to the magnetic liquid sealing device with radial isodirectional magnetization of the permanent magnets, as being matched with the pole shoes at the excircles of the pole shoes respectively, the permanent magnets do not occupy the axial size, the axial size of the magnetic liquid sealing device can be remarkably shortened without changing the pressure endurance capability, and the magnetic liquid sealing device is suitable for places with smaller axial sizes and without limitation on radial sizes.