Abstract: In order to further explore the source of diamond in sand ore and search for primary diamond in Hu'nan Province, the authors used the natural heavy sand measurement method to collect 250 samples of natural heavy sand in Majitang area, Taojiang, Hu'nan Province. Diamond indicates quite a lot of minerals and much quantity. Twelve diamonds were found, which have a single type and are about 0.3mm in diameter, yellow green in color and exhibit hexoctahedron surface; there are 8864 grains of indicating mineral chromium spinels, black-grayish black in color, intensely worn, round granular in shape; there are 2403 grains of ilmenites, black-grayish black in color, relatively weakly worn. According to the distribution characteristics of diamonds and indicator minerals in this area, fourteen anomalous zones were delineated in the study area, including five grade I anomaly area, five grade Ⅱ anomaly area and four grade Ⅲ anomaly area. It is concluded that the distribution of diamond and indicating minerals in this area is extensive, but shows no orientation enrichment, the quantity of diamond in the northern region is large, whereas that in the southern region is small; the amount of the outcropped area in the old strata is large whereas that in the new strata is small. Through the comparative study of diamond and indicative minerals, it is found that the crystal shape, color and grain size are similar to the features of diamond in the Taojiang River stone bridge diabase and the diamond found in the Ningxiang potassium magnesium alloy. It is inferred that the minerals came from the diabase/potassium magnesia porphyry and other types of rock bodies that have not yet been discovered in this area.