Experiments on genetic effect of pigment content in pericarp of black rice grain were conducted with 6 combinations from 3 black pericarp rice varieties with different pigment contents and one non-pigmental variety. Genetic studies indicated that the means of pigment content in F2 generations of 6 crosses were usually within the range of mid-parent, the frequencies of pigment content in pericarp was controlled by quantitative inheritance. On the other hand, a 7 ×7 diallel cross of 6 black pericarp rice cultivars and 1 non-pigmental rice cultivar was made, genetic analysis was conducted by Hayman's model. The results were as follows: the inheritance of pigment content could be described by an additive-dominance model, the alleles for high pigment content were dominant to those for low pigment content, the deep black pericarp was expressed as dominant trait over light black one, and black pericarp was dominant to non-pigmental one, in other words, least number of dominant gene was 2, and the average dominance was within the range of incomplete dominance, the action direction of all dominant locies was consistent, and the heritabilities in broad sence and narrow one were high. In accordance with the results, the problems related to the breeding of rice varieties with deep black pericarp or high pigment content in pericarp and high nutrient qualities were also discussed.