In order to solve the problem that the rape transplanter is mainly semi-automatic and lacks the seedling feeding device matching with the substrate block seedling separating mechanism, a two-way progressive seedling feeding device for rape substrate transplanter was designed. The working process of the seedling delivery device was described, the mechanical properties of the substrate block were measured, the working parameters of the stable transportation of the substrate block were determined, and the kinematic models of the lateral progressive seedling delivery stage and the longitudinal continuous seedling delivery stage were constructed. The single factor experiment and three factor three level quadratic orthogonal combination experiment were carried out with the bottom height of seedling frame, the height of upper guide rod, the longitudinal seedling delivery speed as the factors, the synchronization rate of seedling delivery and the success rate of seedling delivery as the evaluation indexes. The results of single factor test showed that when the bottom height of seedling frame was 5~25mm, the height of upper guide rod was 45~55mm, and the longitudinal seedling feeding speed was 80~140mm/s, the seedling feeding effect was better. The results of quadratic orthogonal combination test showed that when the bottom height of seedling frame was 10.7mm, the height of upper guide rod was 50.0mm, and the longitudinal seedling delivery speed was 140.0mm/s, the seedling delivery synchronization rate was 9454%, and the success rate of seedling delivery was 93.13%. The results of field verification test showed that the seedling delivery synchronization rate was 92.20%, and the success rate of seedling delivery was 88.30%, which met the requirements of rape transplanter. The research result can provide a reference for the structural improvement of the transplanter.