The growth and development characteristics and relationship between the galls and Haloxylon ammodendron were studied through the observation of the morphology and microstructure of the leafy galls in H. ammodendron and the enrichment analysis of differentially expressed genes based on transcriptome sequencing, for the aim to provide a theoretical basis for the coevolution of insect and plant and the pest control of H. ammodendron. The results showed: (1) the growth stage of the leafy galls can be divided into 3 periods: growth period, formation period and decay period. (2) There were obvious differences in the anatomical structure of the leafy gall and the assimilating branch and scale leaf of H. ammodendron in the growing period and the formation period: In the growth period of leafybracted gall, the cuticle is damaged outer epidermal cells, but epidermal cells intact, little morphological differences and tightly stacking, it no palisade cells and kranz anatomy, only spongy tissues with high water content, and the cells are small and dense than that of the assimilation branches and scales, the number of cells is about 2 times the scale, and the diameter of the vascular cylinder is smaller than that of the assimilating branch and scale leaf; In the formation period of leafybracted gall, the cuticle is severely damaged outer epidermal cells, the shape of large differences, loose arrangement, sponge tissue water content is seriously reduced, vascular tissue is not obvious. (3) The expression of gene enrichment related to the normal development of plant cells and photosynthesis in H. ammodendron was downregulated, while the expression of stressrelated enrichment was upregulated. It is considered that the leafy galls of H. ammodendron only promote the growth and development of psyllids, and have no effect on improving the photosynthesis of H. ammodendron.