Abstract: In the paper the contents and forms of aluminum and calcium of soils, as well as their geochemical characteristics in soil-forming processes, in Hainan Island are discussed. Meanwhile, the impacts of both elements on crop growth and human health are also primarily researched. The soils in Hainan Island have the pedogeochemical characteristics that the soils are highly abundant in aluminum and highly deficient in calcium. The total amount of aluminum (Al₂O₃) may be as high as 300 g/kg, but that of calcium is very low or even trace. In the same way, the content of exchangeable aluminum of the soils is high and that of exchangeable calcium is very low. Now, there are about 50 percent area of the soils where plant growth may be impact due to soil aluminum toxicity. The intake of calcium for local people, reflecting on the food, is less than that for the people of whole country as well as the neighboring province. Consequently, the suggestion is recommended that, besides improving soils, cultivating more legume crops, increasing soybean production and developing dairy farm are necessary to build up the people's health.