Police in the city of Guiyang seized 10,500 guns and 120,000 forbidden knives, China Central Television said.
Fifteen people suspected of being part of a criminal gang involved in the manufacturing and trafficking of firearms were arrested, it said.
The gang's distribution network covered Hunan, Guangdong, Sichuan and 27 other provinces, CCTV said.
Gun attacks are rare in China but the government has stepped up efforts against violent crime following a spate of incidents, including a knife attack at a station in Kunming city in March blamed on militants from the western region of Xinjiang.
Last month, police shot dead a man who went on a rampage with a knife killing five people after a dispute between market vendors got out of control.