Armed with a hunting rifle, the bank employee surnamed Liu broke into the hall of the branch of the People's Bank of China in Dashiqiao City and started shooting at point blank.
Police captured the gunman at the scene, state-run Xinhua News Agency reported.
Liu, 51, fired four shots and all the victims were his colleagues.
Preliminary investigation showed that the shooting was due to the disputes about money, but further probe is needed to confirm Liu's motive, the report said.
The injured who were admitted to a hospital are in a stable condition, the report said.