【Objective】Heilongjiang Province is the largest grain-producing province of China, and sits at the starting point of the Selenium (Se)-deficient belt of the country. In the light of the physical conditions and soil distribution in various regions of the province, agricultural soil samples, representative of the regions were collected for analysis of Se distribution and exploration of effects of soil physic-chemical properties on it, with a view to providing some providing scientific bases for the survey of environment background and the study of epi-geochemistry of soil selenium as well as human health. 【Method】More than 400 soil samples from the topsoil layers (0~20 cm) of farmlands all over the province and 21 soil profiles of the major types of soils samples (21 of the province, together with 71 soil samples from genetic horizons of the profiles) were gathered and analyzed for content and distribution of soil Se and their relationships with soil properties, such as pH, SOC (Soil organic carbon) and PSD (Particle size distribution). 【Result】Results show that the content of total selenium ranges from 0.008 to 0.660 mg kg^-1 with a mean value of 0.147 mg kg^-1, which means that on the whole the soils are in the category of Se deficiency or potential Se deficiency, with little in the category of high Se or excessive Se (Se-poisoning). Among the types of soils existing in the province, saline-alkali soil is the lowest in Se content (0.097 mg kg^-1), while Peat soil the highest (0.273 mg kg^-1); In most soil profiles Se accumulates mainly in the surface soil, and declines with soil depth, and in a few of them, Se distribution displays two peaks or one peak in the subsoil layer, too. Among the regions of the province, Daxinganling is the lowest in Se content (0.115 mg kg^-1), while Xiaoxinganling the highest (0.198 mg kg^-1). Among the administrative regions, Daxing’anling is the lowest (0.115 mg kg^-1), while Heihe city the highest (0.228 mg kg^-1). Correlation and regression analysis shows that soil Se content is significantly and positively related to soil total organic carbon (SOC) and soil clay content, but negatively to soil pH. 【Conclusion】So SOC content, clay content and soil pH are the main factors affecting selenium content of the topsoils in the studied area. Besides, soil parent material is also an important factor affecting the distribution of selenium in the soil. Whatever, SOC content plays a crucial role in the distribution and accumulation of Se in the profiles.