To investigate the dewaterability of sludge and its relationship with protein (PN), polysaccharide (PS) of extracellular polymers (EPS) in sludge bioleaching, S⁰was added as substrate with different dosage of S⁰ (0g/L, 2g/L, 4g/L, 6g/L, 8g/L) +10% inoculum for 10 days. Results showed that dissolved PS, PN and sludge specific resistance (SRF) reduced at 0~2days, but increased later, while the bound PN and PS decreased during 0~8d of bioleaching, and slightly increased later. Moreover, the above trend increased with the increasing loadings of S⁰. Statistical results showed that the SRF and dissolved PN, PS had a significantly positive correlation (R=0.861, 0.875, P<0.01), suggesting that the content of dissolved PN and PS were influenced by S⁰, thus affecting the dewatering performance of sludge, in which, the dissolved PS had more effect on the dewatering of sludge. The best bioleaching process for sludge dewatering performance was 8g/L of S⁰ for 2days, followed by 2g/L of S⁰ for 6days. with the SRF 58% and 54% lower than that of the original sludge, respectively. The heavy metal removal rate in the latter case was higher, thus the latter with 30℃, pH dropped to 2.66 was recommended as the optimization conditions.