Her 23-year-old son was knocked out after three topless men ran over to the group and attacked them. Police said the woman's other son, who is 26, suffered a serious cut to his jawline, which left skin hanging from his face.
It happened at the junction of Southcoates Lane and Holderness Road outside The Bank pub at around 8pm on Thursday.
A spokeswoman for Humberside Police said the family was walking past when there was a confrontation between the mum and sons and a group of people drinking outside the pub.
Three men then ran over to the family and punched the woman before assaulting the two men. The mother was unhurt.
Both sons were treated at Hull Royal Infirmary for their injuries. Police attended but could not find the men responsible.
The suspects are three white men, aged between 25 and 45 and were wearing blue jeans.
Police are appealing for anyone with information to call 101.
