A two-year field experiment was conducted to evaluate the ability of biochar to improve the soil environment of intercropping systems. There were two planting systems (maize/soybean, maize/peanut intercropping) coupled with three biochar application rates (0, 15, and 30 t ha^–1). Changes in the soil water content, soil bulk density, temperature, soil nutrients and yield were recorded. Under the influence of rainfall, biochar significantly increased soil water storage at the 0-30 cm soil layer. The maximum increment of soil water storage was 15.5% with the maize/peanut intercropping at 15 t ha^–1 treatment at the tassel stage. Both biochar treatments significantly increased the soil effective accumulated temperature at the seedling stage and jointing stage. The greatest increment in soil effective accumulated temperature was achieved using the maize/peanut intercropping at 15 t ha^–1 treatment. The effects of biochar on soil effective accumulated temperature were weakened at the tasselling, grain filling and mature stages. After biochar application, the soil mineral nitrogen content was significantly reduced at the seeding stage, but significantly increased by 25.2-48.9% at the tasselling and grain filling stages. The soil ammonium and nitrate nitrogen content of the soybean and peanut ridges was significantly higher than those of the corn ridges. The total yield of maize/soybean increased by 12.8-13.7% and the total yield of maize/peanut intercropping increased by 15.9-18.0% relative to the treatment without biochar. Therefore, both 15 t ha^–1 and 30 t ha^–1 effectively regulated the soil water, nutrient and temperature at the jointing, tasselling and grain filling stages, which enhanced the positive effects of intercropping on crop yield. From an analysis of the yield results, it was found that biochar may be more significant in the maize/peanut intercropping system.