THE author thinks that the ore-forming solution is formed not by the near-neutral brine but by the strongacid solutions. Some evidence are the following: (i) The simulating experiments showed that, all near-neutral supergenic water as volcanic hotspring water of Tengchong, K-brine of Mengyejing, seawater of Qingdao, oil-gasses-bearing water of Chitianhua, rain water of Guiyang and CO_2-bearing rain cannot form metal-bearing solutions by heating mixedabove-mentioned supergenic water with ore-source rocks as basalt, ore-bearing carbonate, sandstone andshale. The most content of Cu, Pb, Zn, Hg, Sb, As, Ag in solutions is only (0.3-0.5)×10~(-6).They cannot form any ore deposit. Oppositely, the acid solution of pH=1.0 is easy to form metal-bearingsolutions with every ore-source rocks. The most content of metal in solution is n×10-n×1000 × 10~(-6)i.e. rose in 3-5 grades. The content of metals in humic acid-bearing solutions is variable, perhaps dueto the changes of humic components and content and due to easy-decomposition by oxidation or heating.So the best one in solutions to form ore-forming solution is only the acidic water. THE author thinks that the ore-forming solution is formed not by the near-neutral brine but by the strong acid solution. Some evidence are the following: (i) The simulating experiments showed that, all near-neutral supergenic water as volcanic hotspring water of Tengchong, K-brine of Mengyejing, seawater of Qingdao, oil-gasses-bearing water of Chitianhua, rain water of Guiyang and CO_2-bearing rain can not form metal-bearing solutions by heating mixedabove-mentioned supergenic water with ore-source rocks as basalt The most content of Cu, Pb, Zn, Hg, Sb, As and Ag in solutions is only (0.3-0.5) × 10 -6. They can not form any ore deposit. Oppositely, the acid solution of pH = 1.0 is easy to form metal-bearing solutions with every ore-source rocks. The most content of metal in solution is n × 10-n × 1000 × 10 -6 ie rose in 3- 5 grades. The content of metals in humic acid-bearing solutions is variable, perhaps dueto the changes of humic components and c ontent and due to easy-decomposition by oxidation or heating. The best one in solutions to form ore-forming solution is only the acidic water.