Partial replacement of chemical fertilizers with organic fertilizers is a key path for achieving zero growth in chemical fertilizers in tea gardens. Biochar, a new agricultural soil amendment, has positive effects in optimizing the soil microecological environment. Further understanding the effects of organic fertilizer substitution and biochar application on the soil aggregate stability and organic carbon accumulation in tea gardens, also the synergistic effects, can provide scientific basis for reducing fertilizer application, increasing efficiency, and carbon sequestration and emission reduction in tea gardens. Wet screening method was used to treat seven different fertilizers, namely no fertilization (CK), conventional fertilization (NPK), fertilizer and biochar application (biochar dosage 10 t/hm², NPK+BC10), 50% fertilizer+50% organic fertilizer (OM50), 50% fertilizer+50% organic fertilizer (OM50) combined with different amounts of biochar. The amount of biochar was 10 t/hm² (OM50+BC10), 20 t/hm² (OM50+BC20) and 40 t/hm² (OM50+BC40) for physical grading of soil aggregates. The distribution, structure and stability and the change of organic carbon content in different treated tea plantations were studied. Under the treatment of OM50+BC10, OM50+BC20 and OM50+BC40, the organic carbon reserves of aggregates increased to different degrees compared with the conventional fertilization control treatment. In contrast to the NPK and CK treatments, the replacement of 50% chemical fertilizer with different doses of biochar could significantly improve the organic carbon content of soil>2 mm and 0.25-2.00 mm granular aggregates. The increase rate was ranged from 23.96%-70.87% and 21.87%-49.27%, OM50+BC20 and OM50+BC40 had the most significant treatment effect. Geometric mean diameter (GWD) and mean mass diameter (MWD) in aggregate were in the order CK<NPK<NPK+BC10<OM50<OM50+BC10<OM50+BC20<OM50+BC40. The aggregate content and organic carbon content were the most significant in OM50+BC40 treatment. 50% organic fertilizer replacing 50% fertilizer, different amount of biomass carbon application could significantly increase tea garden soil aggregate, organic carbon content, promote tea garden soil aggregate stability and structure level. Organic fertilizer and biomass carbon is more conducive to improving the stability of soil aggregate and promoting the sequestration of organic carbon. OM50+BC20 and OM50+BC40 treatment showed significant results in improving the stability of soil organic carbon and soil aggregates in tea plantations. Without considering the cost effect, OM50+BC40 is a suitable fertilization scheme; otherwise, OM50+BC20 can be selected.