The man was flown to hospital with injuries to his back after the incident in Dryden Road, next to Moreton School, in Bushbury on Thursday,
The air ambulance landed on the school field before medics treated the man shortly after 3pm.
Nobody has been arrested and West Midlands Police said officers were still investigating the circumstances around the incident.
A spokeswoman for the force said: "Police were called by ambulance colleagues to reports of a stabbing in Dryden Road, Wolverhampton shortly after 3pm.
"A man has been taken to hospital to be treated for injuries to his back, which are not believed to be life threatening.
"Anyone with information can contact us, quoting log number 1554 of 21/03 via Live Chat at west-midlands.police.uk between 8am and midnight, call 101 anytime or contact Crimestoppers anonymously on 0800 555 111."
West Midlands Ambulance Service spokeswoman Claire Brown added: "We were called at 3pm to reports of an assault.
"One ambulance, a paramedic officer and the Midlands Air Ambulance from Cosford, with a MERIT doctor on board, attended the scene.
"They treated one man and airlifted him to hospital."