To achieve high-grade recovery of struvite (MAP, MgNH₄PO₄·6H₂O), two pretreatment methods of anaerobic fermentation and freezing microwave were investigated to promote the release and recovery of nitrogen and phosphorus from the excess sludge. The results showed that the maximum release of phosphorus and ammonia nitrogen reached 224.50 mg·L^-1 (7.24 mmol·L^-1) and 278.17 mg·L^-1 (19.87 mmol·L^-1), respectively, at the fermentation temperature of 30 ℃, the pH of 12 and the fermentation time of 4 days. In the anaerobic fermentation supernatant the molar concentration of phosphate was much less than that of ammonia nitrogen. When the freezing temperature of -20 ℃, the freezing time of 48 h, the initial pH of microwave of 3 and the microwave time of 9 min, the release of phosphorus and ammonia nitrogen was 1011.84 mg·L^-1 (32.64 mmol·L^-1) and 220.82 mg·L^-1 (15.77 mmol·L^-1), respectively. Contrastively, in the frozen + microwave supernatant the molar concentration of ammonia nitrogen was much lower than that of the phosphate. According to the content of nitrogen and phosphorus in the supernatant, the optimal mixed volume ratio of the supernatant with anaerobic fermentation and frozen + microwave was 1∶9. When the molar ratio of Mg∶N∶P was 1.6∶1.4∶1, the highest recovery efficiency of phosphorus and ammonia nitrogen was 99.11% and 73.46%, respectively. The result of X-ray diffraction (XRD) showed that the recovered precipitate was mainly struvite crystal. Mixing the supernatant of two sludge pretreatment methods effectively solved the problems of low recovery resulted from the imbalance of nitrogen and phosphorus. And thus nitrogen and phosphorus from excess sludge could be efficiently recovered in the form of struvite.