The Canadian, a semi-finalist in Melbourne in 2014, had defeated You Xiaodi and Maddison Inglis in the first two rounds of qualifying, but will miss the first Grand Slam of the year for the first time since 2013.
In the second set, Trevisan threatened to run away with it, racing into a 5-0 lead, but Bouchard launched a mini-comeback, breaking back once to save face and limit the Italian to a 6-4, 6-3 win.
Bouchard falls to world No 154 Trevisan in Australian Open qualifying
Elsewhere in qualifying, Harriet Dart defeated another Italian, Giulia Gatto-Monticone, 6-1, 6-3, granting her a second chance at the Australian Open, following her double bagel loss to Maria Sharapova in last year's tournament.
French Open and Wimbledon doubles champion Barbora Krejcikova is also in the main draw for the first time in her career after beating Varvara Lepchenko 6-4, 6-4.
Shelby Rogers, a former Roland Garros quarter-finalist is also through, having defeated fellow American Caroline Dolehide 6-4, 6-4.
In the men's qualifying draw, Ernests Gulbis headlined the action, with the former French Open semi-finalist winning 7-6, 6-2 against India's Prajnesh Gunneswaran.