Abstract: In order to explore the role of compound microbial fertilizer in promoting the growth of tea trees, measurements were conducted on the height, the chlorophyll content and tea polyphenols of tea trees,and the content of ammonium nitrogen, quick-acting phosphorus and effective potassium in the soil after the application of compound microbial fertilizer by direct measurement, tartric acid sub-iron colorimetry, etc.;The results showed that, after applying bacterial fertilizer, the YoY tree height increased by 75.05%, the YoY content of tea polyphenols increased by 11.00%, the YoY chlorophyll content increased by 1.69%, the YoY ammonium nitrogen increased by 201.04%, the YoY quick-acting phosphorus decreased by 6.09%, and the content of effective potassium decreased by 33.06%. It indicated that compound microbial fertilizer improved the absorption of mineral elements and the quality of tea significantly.