The invention relates to a method for injecting a solid retarded acid, which includes: (1) uniformly mixing a solid acidic substance and a natural polymer according to a mass ratio of 0.2-1.2:1 to produce particles with a particle size of 20-70 mesh, and releasing In the coating pan, sprinkle zinc acetate powder, the coating pan rotates at a speed of 100-300 rpm, and at the same time irradiates with infrared light. After rotating for 10-30 minutes, spray the concentration of 92-98% with a spray gun Glycolic acid aqueous solution, stop after spraying for 60-90 minutes, and continue to rotate for 30-60 minutes to obtain solid retarded acid; (2) inject non-reactive liquid and solid retarded acid into the sand mixer, and the solid retarded acid The mass to volume ratio of the non-reactive liquid is 10‑80:100. After the sand mixer is mixed evenly, it is injected into the formation with a fracturing truck. When the solid retarded acid is delivered to the design position, stop the pump, remove the pipeline, and wait After 3‑6 hours, open the well and blow out. The invention has good resistance-reducing performance, is easy to discharge back, reduces construction cost, is beneficial to environmental protection, and has broad market application prospects.