The woman told her son she would buy him a computer if he scored average marks of more than 94% for his school work, the Hong Kong edition of the China Daily reported.
However, she welshed on the deal when he achieved an average of 97%, telling him she could not afford to buy the computer, the newspaper said.
The schoolboy from Xingzheng, Henan province, then went to court asking a judge to make his mother honour the verbal agreement. At the hearing, the judge reconciled the mother and son.
According to the newspaper, the boy gained his knowledge of law after helping his parents with their small business.