The invention belongs to the technical field of in-situ leaching uranium mining and particularly relates to a permeable in-situ leaching uranium mining leaching process for a hydrochloric acid modified sand layer. The purpose is to solve the technical problem that traditional mining processes of sulfuric acid in-situ leaching and alkaline in-situ leaching cannot meet mining requirements under the condition of decreasing of the uranium resource quality. In practical use, the leaching process is stable in control and compact in joining, liquid extracting and injecting capacity is improved, oxidation of uranium minerals is accelerated and achieved, uranium-containing leachate is obtained, and the condition of production concentration treatment in later period can be met. In the leaching mining process at a Shihongtan 1# mining area, by adopting the leaching process, the liquid injecting capacity is increased from 108 m<3>/h to 132 m<3>/h; oxygen is dissolved effectively and injected into the ore-containing sand layer, the oxygen content in the leachate is 18 mg/l, the average peak value of the uranium concentration of the leachate is 27.8 mg/l, and the uranium concentration peak value of a single well is 64 mg/l; and accordingly the effects that the uranium resource of the mining area is exploited, and the recovery rate of the uranium resource of the mining area reaches 76.5% are achieved.