A field experiment was conducted to explore the effect of vermicompost on the root absorption characteristics and humus composition of cowpea rhizosphere soil. The effects of different treatments, i.e., CK (neither urea nor vermicompost was applied), CF (100% of nitrogen was provided by urea), VC(100% of nitrogen was provided by vermicompost), and VC+CF (vermicompost and urea each provided 50% of nitrogen) on soil physical property, root activity, root morphological characteristics and root exudates, as well as humus composition in the rhizosphere soil of cowpea were studied. The results indicated that in comparison with CF treatment, the VC and VC+CF treatments evidently decreased soil bulk density, and significantly increased soil total porosity, capillary porosity and non-capillary porosity. Different fertilization treatments had no significant effect on root characteristics and humus composition in the rhizosphere soil at the seedling stage of cowpea. While at the stretch tendril period and flowering and pods formation stage, VC+CF treatment significantly increased root activity and obviously increased the total root length, specific root length, root surface area, root volume and root tip number, while the root average diameter was apparently decreased compared with CF treatment. The root surface area in the VC+CF treatment was increased by 144.88%, 80.73% and 36.82% at the flowering and pods formation stage compared with the treatments of CK, CF and VC, respectively. Meanwhile, VC+CF treatment also significantly increased the contents of root exudates and humic acid, and increased the ratio of humic acid to fulvic acid, showing 4519%, 37.06% and 7.69% increases in humic acid content over the treatments of CK, CF and VC at the flowering and pods formation stage, respectively. Additionally, the VC+CF treatment could significantly increase yield and improve quality of cowpea, which had statistically significant differences with other treatments. Along with the extension of cowpea growth period, the impact of vermicompost co-applied with urea on root growth and soil physic-chemical properties of cowpea presented a gradually increasing trend. As a result, the application of vermicompost co-applied with urea was beneficial to root absorption characteristics and humus composition in the rhizosphere soil and soil nutrient-supply capacity improvement as well as growth with high-yield and high-quality of cowpea.