The late night attack in Glasgow Green happened on Saturday, April 19, at around 11.30 pm.
A 27-year-old woman was walking from the Saltmarket through the East End park on her way home from work when she was approached.
The man came from behind and pushed her to the ground, before sexually assaulting her.
The young woman struggled with her attacker, who is described as white, around 5' 8" inches with short dark hair.
He fled the scene, leaving her in shock.
Detective Inspector Diane Caldwell, of London Road Police Office, said today: "This was an extremely upsetting and frightening ordeal that this woman experienced. Although she did not require hospital treatment, she is badly shaken as a result of the incident.
"A forensic examination is taking place at the area where this attack took place within the park.
"Detectives are also carrying out further enquiries in the local area and gathering CCTV footage in an effort to gather more information on the man responsible.
"It is vital that we trace this man, and I would urge anyone who may have been in the park and witnessed this assault take place, or who may have seen him acting suspiciously or running through the park to contact police as a matter of urgency."
Anyone with information is asked to contact Police Scotland on 101 or speak to Crimestoppers anonymously on 0800 555 111.