Xinhua News Agency said Wednesday that Lei Sen allegedly made a bomb using firecrackers, wires and a battery, then set it off last October using a cell phone. The report said the motive was "to avenge a personal grudge against society," but did not elaborate.
An American who was studying in China and passing by at the time received minor leg injuries.
Lei faces a charge of endangering public security and if convicted could be sentenced to 10 years in prison. A court date has not been set.