In this paper, a novel decoupling modular permanent magnet flux-switching linear motor (PMFSLM) is proposed. The primary iron core of the motor is a nonsegmented structure without magnetic coupling among different modules. In contrast to a normal PMFSLM driven by a sinusoidal current, the proposed PMFSLM adopts square-wave current driving. On the basis of structure and working characteristics, a piecewise linear permeance model of a single-module PMFSLM is presented, and a specific design method of the novel modular three-phase PMFSLM is proposed. The proposed design method aims at reducing the cogging force and force ripple of a three-phase PMFSLM. Through further electromagnetic analysis, a set of structural parameters is proposed, based on which finite-element analysis (FEA) is conducted. FEA results show that the design aim is realized even with the influence of armature winding commutation. Prototype experiments of a single-module PMFSLM are performed, and experimental results agree well with FEA results. The findings of this paper verify the effectiveness and practicability of the novel modular PMFSLM and the proposed design method.