Zhang, who beat Ronnie O’Sullivan in the last 16 on Thursday, stormed into a 4-0 lead and didn't look back as he booked his maiden ranking event final with relative ease.
The 31-year-old turned professional in the 2009/10 season but has only reached one quarter-final before this week - the Welsh Open last year.
Zhang - dubbed 'the Mighty Mouse' - will now face Judd Trump, who stormed back to beat John Higgins 6-5 in the afternoon session, in the two-session final on Sunday.
"I am feeling good," Zhang told Eurosport. "I play Judd and can play well, (I) want to make trouble for him.
"I want to keep going, to do better in the final. I have confidence."
Liu had previously stunned Ding Junhui in his quarter-final but appeared to be overawed by the world number 57 - who is ranked 32 places above him - after reaching the semi-final for the first time.
