Serving a crucial role in the redistribution of energy flux and nutrient cycles in the environment, microalgae have garnered wide attention due to their excellent ability in wastewater phycoremediation with simultaneous resources recovery to synthesize valuable bioproducts for biofuel and other applications. Anaerobic digestate of dairy wastewater is rich in organic carbon and nutrients (N and P), which can be efficiently utilized for algal cultivation to generate biomass. This study investigated the performance of microalgae in dairy wastewater treatment by growing Chlorella sorokiniana SU-1 on untreated anaerobic digestate of dairy wastewater to achieve satisfactory chemical oxygen demand (COD)/nutrients removal and bioproduct synthesis. High biomass concentration of 4.8 ± 0.08 g/L with biomass compositions of 47.3 ± 1% carbohydrate, 29.3 ± 11% protein, and 4.3 ± 3% lipid content as well as outstanding wastewater treatment performance (91.3 ± 3% of COD, 92.1 ± 2% of TP, and 96.3% ± 1 of TN) was obtained under the optimized condition of 100% wastewater, inoculum size of 1 g/L and CO 2 aeration rate of 400 ml/min. The compositions of the treated effluent satisfied the regulation limits of Taiwan Dairy Wastewater Discharge Standards (COD < 400 mg/L, TP < 8 mg/L, and TN < 80 mg/L). This novel approach demonstrated satisfactory results for simultaneous anaerobic digestate of dairy wastewater treatment and biochemical production for future applications.