The 23-year-old, who was training with Rangers last season, will pen a contract from August 1.
Blackwood told qpr.co.uk: “I am very happy to sign for QPR.
“I worked hard throughout the backend of last season, and the start of this, and the hard work has paid off.
“I’m a striker who likes to play on the shoulder of the last man, use my pace, and I’m a goalscorer.
“My personal target this season is to get league appearances. I know I’m good enough, but I have to prove to the manager and the rest of the team that I deserve to be involved. That’s my aim.
“Under Chris Ramsey, you know that every day you train there is a chance you will be involved. It gives you that extra incentive, you don’t need any more motivation than that.”
Head coach Ramsey added: “Tyler is a late developer. He went down the education route initially, and studied in America.
“He has trained with us for a few months and we believe he deserves this chance.”