Abstract: In mechanized plug seedling production, it is necessary to eliminate inferior plug seedlings and replant healthy plug seedlings with transplanter. In order to improve the plug seedling transplanting efficiency, plug seedling transplanting path would be planned. In this paper, the Clone Selection Algorithm(CSA) model and Immune Genetic Algorithm(IGA) model were constructed to solve the problem of transplanting path optimization of plug seedlings in greenhouse. Compared with the common sequence method and the Genetic Algorithm(GA), the simulation and verification tests of the transplanting path planning were carried out with 50-hole, 72-hole, and 128-hole plug trays. Set the population size in the CSA model to 40, the mutation probability to 0.4, and the number of clones to 10. Set the total population size in the IGA model to 40 (of which the memory cell bank capacity was 10), and the crossover probability to 0.5, the mutation probability was 0.4, and the diversity evaluation parameter was 0.95. The results showed that CSA and IGA model designed in this paper could achieve the purpose of optimizing the plug seedling transplanting path. The planned path length of the two models was similar, and the planned path length of two models was significantly shortened compared with the common sequence method and the GA. In the verification tests, the planned path length of common sequence method, GA model, CSA model and IGA model were 52 998, 50 807, 48 977 and 48 945 mm respectively. Compared with the common sequence method and the GA, the planned path length of CSA model and IGA model were shortened by 7.59% and 7.65%, and shortened by 3.60% and 3.66% compared with the GA model. The path planning efficiency of IGA model was higher than that of the CSA model, the calculation time of GA model, CSA model and IGA model was 3.23, 5.86 and 2.72 s respectively, the calculation time of IGA model was 15.79% less than that of the GA model. The models designed in this paper were suitable for path optimization of various-size plug seedlings automatic transplanting in greenhouse, it only needed to get the coordinates of plug seedlings according to the actual needs.