Along with the seizure of the drugs, police also arrested five suspects in the case, China's Xinhua news agency reported.
Three of the suspects were arrested in southwest China's Yunnan province while they were allegedly transporting the heroin to Ningxia. The other two were taken into custody at a hotel in Yinchuan.
If convicted, the suspects face at least 15 years in prison.
Police said this was the largest single illegal drug shipment seized as it was being smuggled into the region.
In 2012, law enforcement officials seized 8 tons of heroin, 17.6 tons of methamphetamine, 5.1 tons of ketamine and more than 6,393 tons of chemicals used to make drugs, Xinhua said.