Abstract: To investigate the effects of pyrroloquinoline quinone on the growth of pepper and the soil, physical and chemical properties, microbial activity of the soil and the growth of pepper were measured in the potted peppers applied by different concentrations and methods of pyrroloquinoline quinone. The results showed that pyrroloquinoline quinone had no significant effect or no effect on soil bulk density, soil porosity, soil fungi, actinomycetes, soil available nitrogen, soil available potassium, Vc content and soluble protein content in pepper fruits, but could increase the number of soil bacteria and total microorganisms, soil available phosphorus content and pepper growth as the fruit weight, plant weight, the root activity and soluble sugar content of pepper fruit. The increase of soil bacteria, total microorganisms and soil available phosphorus by root irrigation was better than spraying treatment, and spraying treatment shows better effect on the improvement of pepper growth, yield and quality. It is suggested to apply pyrroloquinoline quinone combining irrigation with spraying.