In this study, a pot experiment of wheat-maize rotation was carried out to explore the mechanism of increasing yield and enhancing effect, and the influence on soil nutrient status of alginate and controlled release urea application. Through the pot experiment with nitrogen blank (CK0) as the control, 9 treatments were set up:normal urea (N2A0), normal urea with alginic acid (N2A1), controlled-release urea (CN2A0), controlled-release urea with alginic acid (CN2A1), reducing nitrogen 30% of urea (N1A0), reducing nitrogen 30% of urea with alginic acid (N1A1), reducing nitrogen 30% of controlled-release urea (CN1A0), reducing nitrogen 30% controlled-release urea with alginic acid (CN1A1). The results showed that the wheat and maize yield of the treatment combined application of controlled-release urea with alginic acid (CN2A1) was the highest with 98.22 and 134.84 g/pot. Compared with the treatment of controlled-release urea, the maize yield of CN2A1 was significantly increased by 16.38% (P<0.05) and the N use efficiency increased by 17.79% (P<0.05). Compared with reducing nitrogen 30% of controlled-release urea (CN1A0), the yields of wheat and maize in the treatment of reducing nitrogen 30% controlled-release urea with alginic acid (CN1A1) was significantly increased by 15.92% and 26.05% (P<0.05), respectively, and the N use efficiency was significantly increased (P<0.05). In addition, the leaf transpiration rate, SPAD value and leaf area index of treatments fertilized with alginic acid were increased compared with those without alginic acid. Compared with the treatments without alginic acid, the controlled-release urea combined with alginic acid significantly increased the contents of NO₃^--N and NH₄⁺-N in the soil at the jointing stage of wheat and flaring stage of maize, and significantly increased the content of soil available potassium at the flaring stage of maize. Combined application of alginic acid and controlled-release urea significantly increased the supply intensity and capacity of soil available N and K, and promoted the growth and yield of wheat and maize.