Biomass ash fertilizer developed from biomass combustion residues is rich in mineral nutrition. In this article, component characteristics of biomass ashes were analyzed and biomass ash fertilizer was used to study its effects on the growth and quality of the red bayberry (Biqi and Dongkui cultivars). Results showed that, biomass ashes had high concentrations in nutrients such as K, Si, Ca and Mg, the concentrations of heavy metals were also lower than national standards; biomass ash fertilizer increased fruit setting rate and high quality fruit rate significantly compared with the other two kinds of fertilizers and the control, increased the total soluble solid (TSS), sugar, and Vc contents as well as weight per fruit significantly compared to the common compound fertilizers and the control; Dongkui bayberry and Biqi bayberry increased the yields by 26%, 27% separately, shortened the maturity date. Therefore, biomass ash fertilizer can be used to promote the quality of the red bayberry, thus can alleviate its risk of environmental pollution.