Abstract: The paper aims to study the accurate water and fertilizer management technology of pepper in new organic substrate. 【methods】Pepper variety "Sujiao 5"and T8 optimal matrix formula according to early study methods was used as test material and substrate separately. The experiment scheme was designed by means of second order regression orthogonal experiment with 4 factors and 5 levels. The effects of different combinations of water and fertilizer on pepper yield, fruit quality, photosynthetic parameters, coupling effect of nitrogen (N), phosphorus (P2O5) and potassium (K2O) fertilizer and water was analyzed. 【results】The results showed that low level nitrogen fertilizer and high level of substrate moisture can improve the photosynthesis and yield of pepper in organic substrate cultivation; phosphorus application did not affect the transpiration rate. The interactive effects of nitrogen, phosphorus, potassium fertilizer and water on the yield of pepper were as follows: nitrogen and water>potassium and water>phosphorus and water>phosphorus and potassium>nitrogen and potassium>nitrogen and phosphorus. When N 0.88g, P2O5 0.40g, K2O 3.31g was applied to per pepper plant as the basal fertilizer and matrix moisture content was 63.53% can get the highest yield of pepper. 【conclusion】Confirmatory experiment results showed that the model was accurate and reliable.