In this paper, a method of restraining the cogging force in tubular permanent magnet linear motor with multi-segment primary based on primary iron-cores shifting is proposed, the mechanism of weakening cogging force in tubular permanent magnet linear motor with primary iron-cores shifting is analyzed based on the energy method., and the formula of arranging the primary iron-cores are appropriately illustrated. The studies show that the Back-EMF of each primary iron-core is distributed with primary iron-cores shifting, and the equivalent winding distribution factor of Tubular Permanent-magnet Linear Synchronous Motors with Multi-Segment Primary are Deduced. Finite element analysis and experimental results show that Cogging force and harmonic Back-EMF is effectively suppressed, no-load EMF waveform is more sinusoidal.