James Robertson, 19, was wearing a balaclava when he struck as the 22-year-old walked along Mastrick Road in February.
He escaped with items including her iPod, but was later traced by police.
Robertson, who admitted the crime, was jailed for 50 months at the High Court in Glasgow. He will be monitored for two years after his release.
Defence counsel Ronnie Renucci said: "Mr Robertson was under the influence of valium at the time.
"He has an unenviable record, if he carries on like this he will spend most of his adult life in and out of prison."
Judge Lord Beckett told Robertson: "I'm concerned to make sure that the public is protected from serious harm from you when you are released."
A man who robbed a woman at knifepoint as she walked to work in Aberdeen has been jailed.