A filed experiment started in 2010 was conducted to examine the effects of successive maize straw and its biochar amendment on soil fertility, wheat production and microbial community structure. There were 5 treatments:CK (no straw and no biochar), 6 t/(hm²·a) maize straw (Straw), 2.4 t/(hm²·a)biochar (BC1), 6 t/(hm²·a)biochar (BC3), and 12 t/(hm²·a)biochar (BC5). The results showed that BC5 significantly increased wheat yields in 2021, compared with CK, wheat yields with biochars averagely increased by 15%. After 11 years of continuous addition, soil bulk density decreased from 1.06 g/cm³ (CK) to 0.73 g/cm³ (BC5), and total carbon increased from 14.9 g/kg (CK) to 83.8 g/kg (BC5). Soil available nitrogen, available phosphorus and available potassium increased with the application rates, following the order of BC5>BC3>BC1>Straw ≥ CK. No significant change was found in the diversity of bacterial communities under different treatments, while BC5 slightly increased fungal diversity. PICRUSt2 results showed that biochar addition significantly increased the abundance of C-fixation related functional genes, while decreased the abundance of C-degradation related functional genes.