A native of Wenzhou, Zhejiang. A renowned forensic scientist. Wang Yu was studious from a young age, with a particular emphasis on law. He joined the military at a young age and served as a local official, diligent and efficient in his duties. During a year of famine, the local magistrate was at a loss, but through Wang Yu's efforts, government grain was distributed, saving the people. Later, he was promoted to the position of salt official in Hangzhou and handled legal documents, frequently participating in autopsies, accumulating rich experience. He served as the chief clerk of the Hangzhou circuit and later transferred to Huzhou as a record keeper. He retired and eventually became the magistrate of Yueqing County in Wenzhou, holding the title of Chengzhi Lang.

Throughout his life, Wang Yu focused on law and authored Wuyuanlu, Qinxu Ji, Lifang Shu, and Xingming Tongyi, among other books, which were widely referenced by those in governance. Wuyuanlu gained fame both domestically and internationally.

After retiring, Wang Yu lived in Yongjia County, where he was highly respected by the local community. He provided assistance to those in need, and in the sixth year of the Zhizheng era (1346), at the age of 86, he passed away and was buried in his hometown, Ma'ao.