Considering the global energy crisis, developing renewable biomass energy has become an urgent strategic need. In order to better utilize biomass resources, wheat straw was used as raw material. Findings from enzymatic hydrolysis, saccharification assays, and Scanning Electron Microscopy (SEM) characterization of pretreated wheat straw confirmed that the weak alkali-oxidation pretreatment (2% NaHCO + 2% HO) effectively eliminated lignin with simultaneous preservation of cellulose and hemicellulose fractions of wheat straw under relatively mild pretreatment conditions (50 min, 130°C, and solid-liquid ratio of 1:10). Enzymatic hydrolysis and saccharification experiments revealed that ligninases enhanced the hydrolysis efficiency of pretreated wheat straw, with laccase emerging as the most impactful component among these ligninases. Under the conditions of cellulase 20 U/g, xylanase 10 U/g, laccase 4 U/g, lignin peroxidase 6 U/g and manganese peroxidase 2 U/g, the combined sugars reached a maximum of 108.4 ± 0.6 mmol/L, which was 17.8% higher than that of the group without ligninases. Finally, ethanol was produced by fermenting both glucose and xylose in the fermentation broth, and ethanol fermentation conditions of engineered Saccharomyces cerevisiae strain WXY12 were optimized, with peptone as the nitrogen source and MgSO as the metal ion inducer, temperature at 32°C, rotational speed at 130 r/min, and inoculation amount of 1% (v/v). Under these conditions, the highest ethanol concentration reached 7.6 ± 0.2 g/L, corresponding to an ethanol yield of 20.9 g per 100 g of raw wheat straw, thereby establishing a robust theoretical basis for the efficient valorization of biomass resources.