This paper presents a structure of the ladder shape conductors to enhance thrust force of the linear induction motor. In the analysis, Four models may implement to the structure: semiopen parallel slots flats-type aluminum sheet(SPSF), semiopen parallel slots ladder-type aluminum sheet(SPSL), open parallel slots flats-type aluminum sheet(OPSF) and open parallel slots ladder-type aluminum sheet (OPSL). Thrust forces and thrust ripples are calculated under different aluminum sheet and back iron sheet thickness. Simulation results reveal that ladder aluminum sheet add back iron is possible to increase thrust force. Also, as the aluminum sheet get thinner, the effective air-gap will get smaller, and as a result, the thrust force will become bigger. Open parallel slots Ladder-type aluminum sheet has good thrust characteristics. The simulation data can be used as reference basis when estimating real linear motor performances.