Qi Zhihua, 52, and Qi Zhifeng, 49, allegedly murdered seven people using homemade guns in three cases in 1989, 1992, and 1993 in the city of Siping, a local police officer said at a press conference.
The two men are brothers.
In the 1993 case, the head of the city's taxation bureau surnamed Zhang and his 18-year-old son were killed after Zhang refused to give the brothers jobs at the taxation bureau. They also stole some cash before escaping.
The two also allegedly killed two faculty members at a high school in a robbery, and a 45-year-old woman and her two daughters at their home in Siping.
The suspects were caught in Inner Mongolia Autonomous Region on Tuesday after police combed registration information and compared photos, confirming "Qin Zhonghua" and "Qin Zhongfeng" registered in Inner Mongolia to be the Qi brothers.
Murders involving guns sometimes occurred up to the early 1990s. In 1996, China enacted an arms management law, banning civilians from possessing guns.