The invention discloses a primary iron core of a linear induction motor. The primary iron core comprises a primary punching sheet, a draw plate, a screw rod and tooth supports. The tooth supports are arranged at the two ends of the primary punching sheet and the draw plate, the tooth supports and the primary punching sheet are connected through the screw rod, and the primary punching sheet and the draw plate are connected through a fastener. The primary iron core of the linear induction motor has the advantages of being simple in manufacturing process, improving the production efficiency, decreasing the cost and the like.