Two start-up strategies of upflow anaerobic sludge blanket (UASB) reactor for treatment of pharmaceutical wastewater were investigated. The results showed that both of them were workable. Compared with the strategy that started up the reactor directly using chloromycetin wastewater, the strategy that started up the reactor first using mixed wastewater and then using chloromycetin wastewater could save time by 23%. When the latter strategy was adopted the development of sludge activity fluctuated more largely and its final activity was lower, but the sludge grew faster in the course of start-up.