Yang Xinhai was born on July 17, 1968, in Zhengyang County, Henan, China. He was the youngest of four children in his family. They were among the poorest families in their village, which made life difficult for them. Yang was known to be clever but also very introverted. He did not enjoy being around many people and preferred to keep to himself.

Yang dropped out of school in 1985, when he was 17 years old. After leaving school, he chose not to return home. Instead, he traveled around China and found work as a laborer. He took on various jobs and moved from place to place during this time.

In the late 1980s, he faced legal troubles and was sentenced to labor camps for theft. These incidents occurred in 1988 and 1991. Later, in 1996, he was sentenced to five years in prison for attempted rape. He was released in 1999.

Yang Xinhai committed a series of brutal killings in China from 1999 to 2003. His crimes occurred in several provinces, including Anhui, Hebei, Henan, and Shandong. At night, Yang would break into the homes of his victims, often targeting farmers. He used weapons such as axes, hammers, and shovels to murder the occupants. In many cases, he killed entire families.

During his killing spree, Yang showed a pattern of violence and brutality. His attacks were not limited to murders; they also included sexual assaults. On one occasion, he killed a father and a six-year-old girl and attacked a pregnant woman, who suffered serious injuries but survived.

Yang's last killings took place in August 2003. His violent actions made him one of the most notorious serial killers in China. On November 3, 2003, he was arrested during a police check in Cangzhou, Hebei. It was discovered that he was wanted for multiple murders across four provinces.

After his arrest, Yang was taken to trial. On February 1, 2004, he was sentenced to death for his crimes. The court labeled his actions as one of the longest and most horrific killing sprees in the country's history. Yang Xinhai was executed by firing squad on February 14, 2004.