Abstract: In order to explore the effect of biochar base fertilizer on the improvement of fruit quality of the weak Myrica rubra, by using the three varieties of Myrica rubra (Dongkui, Biqizhong, and Zaotanmei 8801) as the experimental materials, and taking the conventional fertilizer treatment as the control group (CK), three treatments of biochar base fertilizer, including 2.5 kg·plant^-1·year^-1 (L1), 5.0 kg·plant^-1·year^-1 (L2), and 10.0 kg·plant^-1·year^-1 (L3) were set to study the effects of different amounts of biochar base fertilizer on the fruit size (vertical diameter and transverse diameter), fruit quality, fruit color, soluble solid content and vitamin C content of the three different varieties of weak Myrica rubra (Dongkui, Biqizhong, and Zaotanmei 8801). The results showed that the application of biochar base fertilizer had different effects on the fruit quality of weak Myrica rubra, and the difference of each quality index was related to the different varieties of Myrica rubra and the application amount of biochar base fertilizer. Compared with CK, when the application amount of biochar base fertilizer was 10.0 kg·plant^-1·year^-1, the content of vitamin C in the fruit of Dongkui was significantly increased by 23.3%; the single fruit weight, soluble solid content and vitamin C content of Biqizhong was increased by 19.93%, 7.76% and 10.56% compared with CK, respectively. However, when the application amount of biochar base fertilizer was 5.0 kg·plant^-1·year^-1, the single fruit weight of Zaotanmei 8801 was increased by 16.06% compared with CK. In conclusion, the biochar base fertilizer had certain improvement effect on the fruit quality of weak Myrica rubra, so it was suggested to moderately popularize in production.