The invention relates to a planting method of lagerstroemia indica. The planting method comprises the following steps: 1) seedling nursery construction; 2) seed treatment; 3) sowing; and 4) transplantation. A sowing technology is combined on the basis of seedling nursery construction and seed treatment, and the growth situation of lagerstroemia indica is sufficiently considered, so that the emergence rate and survival rate of seedlings and transplants are effectively guaranteed. Many-year practical experience proves that the germination rate and germination potential of seeds can be effectively increased due to the adoption of seed treatment and seedling nursery fertilizer and water management in the planting method; and meanwhile, a double-layer greenhouse is utilized to provide a favorable growth environment for young seedlings, so that the growth speed and growth vigor of plants are increased.