In this paper, a quasi-Halbach magnetization structure of permanent magnet tubular linear generator (PMTLG) with bulged stators and auxiliary slots is proposed to reduce the detent force. In the meantime, the detent force for the structure of 9 PM poles 10 winding slots and the conventional one of 8 PM poles 12 winding slots is compared by using Fourier analysis and finite element analysis (FEA). The theoretical and FEA show that 87.18% detent force can be removed through changing the length of the bulged stator. Finally, a prototype is manufactured to verify that the detent force can be reduced efficiently by applying this method.