Bouchard, the No. 5 seed, defeated Kurumi Nara 6-2, 6-2 in Saturday's semifinals while the third-seeded Stosur raced by No. 6-seeded Madison Keys 6-1, 6-2.
Bouchard won two-thirds of the points on serve and dropped her serve just once on the day. She took 54 percent of the points off Nara's serve and finishing off five of her nine break chances.
Stosur was on the court just 61 minutes in dispatching Keys. Stosur lost only 12 points in her eight games serving and converted four breaks in setting up a second straight match against a teenager. Keys, who was in her first WTA semifinal, is 18 and Bouchard is 19.
Stosur, 29, is 4-12 in previous finals appearances. She won the Southern California Open in August, which was her first title since winning the U.S. Open in 2011. She lost in three championship matches between those titles. Bouchard will be appearing in her first final.
Bouchard claimed a win in her only previous meeting with Stosur. She was ahead 6-1, 2-0 in a Round-of-16 match at Charleston, S.C., in April when Stosur retired because of a leg injury.
Sunday's Japan Women's Open champion will take home $40,000 while the runner-up check is worth $20,000. Keys and Nara each earned $10,425 as semifinalists.