In order to investigate the selenium (Se) content of soil-crop system and its influencing factors in a typical Se-enriched Isohumsols area of northeast China, Hailun City was taken as the study area, the physicochemical properties, total Se and available Se contents in surface soils (0-20 cm), and Se contents in edible portions of crops (rice, soybean and maize) were analyzed. Results showed that soil total Se content was relatively high, with an average value of 0.303 mg/kg, yet Se activation rate (proportion of available Se to total Se) was low with an average value of 0.018 mg/kg for available Se. Both total and available Se contents in soil had obvious spatial distribution characteristics, and the high value areas were mainly distributed in the northwestern and central regions (Yonghe, Aimin, Xiangrong and Changfa towns). For the 3 main crops, Se content from high to low was rice (0.028 mg/kg) > soybean (0.014 mg/kg) > maize (0.007 mg/kg). Correlation analysis showed that the main influencing factors of soil Se content were soil organic matter, total nitrogen, CEC and clay contents, and high organic matter content inhibited soil Se uptake by rice and maize. This study provides data support from planting area to crop type selection for the development and utilization of Se-enriched soil in the study area.