Ma Yongdong, a farmer in Honghe Town of Pengyang County, murdered his wife, his parents-in-law and grandparents-in-law, and his wife's nieces, a court in Ningxia Hui Autonomous Region ruled.
Ma brought a knife to the house of his parents-in-law to demand his wife return home, police said.
When she rejected him, Ma stabbed his pregnant wife, the wife's two nieces, parents-in-law and grandparents-in-law to death, police was quoted as saying by state-run Xinhua News Agency.
Ma confessed to the crimes during the investigation, the police said.