[Objective] To investigate the effects of biochar combined with nitrification/urease inhibitors and straw mulching on nitrogen and phosphorus leaching in tea plantations under field conditions, this study aims to provide a scientific basis for controlling nitrogen and phosphorus leaching in tea plantation. [Methods] In this study, a tea plantation in red soil hills in subtropical areas was selected as the research object. Five treatments were set: no fertilization (CK), conventional fertilization (CON), addition of biochar (BC), biochar and nitrification inhibitor and urease inhibitor (BNI) and straw mulching (RS). During the one-year observation period, the soil properties change and leaching losses of nitrogen and phosphorus under natural rainfall conditions were monitored. [Results] During the observation period, compared with CON treatment, the mass fraction of ammonium nitrogen and nitrate nitrogen in soil treated by BNI was the highest and was 2.8% and 72.8% higher, respectively. The high mass fraction of ammonium nitrogen and nitrate nitrogen in soil treated by BNI promoted the increase of total nitrogen concentration in leaching solution. Soil nitrogen and phosphorus leaching in each treatment mainly occurred in the rainy period of spring and summer. The leaching coefficient of BC treatment was the highest (24.3%), and that of RS treatment was the lowest (8.3%). As for the total nitrogen loss of leaching solution, BNI treatment (275.0 kg/hm2) was the highest, RS treatment (65.9 kg/hm2) was the lowest; As for the total phosphorus loss in the leaching solution, the loss form was mainly granular phosphorus, the highest in BC treatment (201.5 g/hm2) and the lowest in RS treatment (32.4 g/hm2). Compared with CON treatment, the total nitrogen loss of RS treatment solution was reduced by 43.6%. The total phosphorus loss of BNI and RS treatment was reduced by 39.1% and 77.2%, respectively. [Conclusion] Combining the available nutrient content of soil plants in tea plantation and the control ability of nitrogen and phosphorus leaching, straw mulching is an effective management measure to reduce nitrogen and phosphorus loss in tea plantation.