Persulfate (S₂O₈^2-) and its activations were investigated, including ferrous (Fe²⁺), zero-valent iron (ZVI) and ultrasonic (US), on waste activated sludge (WAS) disintegration and acidification. Experimental results showed that S₂O₈^2- effectively disintegrated WAS flocs matrix and further enhanced short-chain fatty acids (SCFAs) production, compared with that obtained from un-pretreated WAS. In addition, activated S₂O₈^2- presented better WAS hydrolysis and acidification performance over un-activated S₂O₈^2- test. The lysis rates of Fe²⁺, ZVI and US activated S₂O₈^2- groups reached to 42.6%, 36.5% and 32.9%, respectively, which were about 10.6%~20.3% higher than that obtained in the non-activated test (22.3%). The maximum SCFAs concentration in the aforementioned three activated tests were 8052, 6613, 4996mg COD/L, respectively, while that was only 3296mg COD/L in non-activated test. Furthermore, the release of organics and the distribution of generated SCFAs were also affected by S₂O₈^2- activations. From the environmental and economic perspective, the S₂O₈^2-+Fe²⁺ system played more significant role for enhancing the SCFAs recovery from WAS fermentation.