By using a Lab-scale Expanded Granular Sludge Bed (EGSB) reactor, the strategies of start-up and the changes of characteristics of granular sludge before and after start-up were investigated. In the first stage, the pentachlorophenol (PCP) concentration in wastewater was fixed at 5 mg/L, and the organic loading rate (OLR) gradually increased. The OLR increased to 5.4 kg COD/(m(3)-reactor d) after 25 days. Then began the second stage, OLR was stabilized as 5 kg COD/(m(3)-reactor d), while the PCP concentration was gradually increased. The PCP loading rate increased to 94.7 mg/(L-reactor d) in 63 days after the second stage start-up, the COD removal and PCP removal were 91.2% and 99.6% respectively. The EGSB reactor has the ability to hear PCP overloading to some extent. After the start-up was finished, the settlement velocity of granular sludge increased, the specific methanogenic activity of sludge and dechlorination rate of PCP were apparently increased. The results show that the two-stage start-up strategy is appropriate.