He will play for the title Sunday against Nicolas Almagro in a match between Spaniards. Almargo defeated Philipp Kohlschreiber 6-2, 6-1 in the other semifinal to advance to his second clay-court final of the year.
"Almagro will be a tough rival," Nadal said. "He will come out aggressive as always. My goal is not to find myself in defensive positions all the time, and even though it will be tough, try to move him around."
The start of Nadal's match was delayed because of rain. He overcame an early break and dominated the rest of the way, with Raonic's big serve doing little damage.
Nadal has won 38 straight matches on the Real Club de Tenis's outdoor red clay. His last loss in Barcelona came 10 years ago to Spain's current Davis Cup captain, Alex Corretja. Nadal is now ranked fifth and has reached six straight finals — winning three — since returning from a seven-month knee injury layoff.
He said his long absence makes him value his chance at a title.
"I can't consider this just one more final," the 26-year-old Nadal said. "With everything I have been through over the last few months, one never knows when all this will come to an end. Every chance I have to win a title is in itself maximum motivation. I never imagined reaching six finals in a row."
His eight-year winning run at Monte Carlo ended last weekend when he lost in the final to top-ranked Novak Djokovic.
Both Nadal and Almagro arrive in good form to the final with neither having dropped a set. However, Nadal is 9-0 against Almagro in career meetings.
In the semifinal, Raonic started strong and broke Nadal to love to go up 2-0. But after that initial misstep, Nadal didn't give up a single break chance while converting 5 of 11 to ease past his rival.
Nadal finished off the first set with a slam after wearing Raonic down with a series of drives to work his way to the net. The Canadian soon crumbled and ceded the match point by hitting wide.
"I understood the way to play (Raonic). Tall players have difficulties with shots at their feet," Nadal said of the 6-foot-5 Canadian.
Almagro will play his first final at Barcelona after falling in his two previous appearances in the semifinals.
He dominated Kohlschreiber, hitting nine aces and breaking the German four times.
"To beat Rafa, a lot of things have to go your way," Almagro said. "I'm calm and believe in my tennis, which before was more erratic. Now I believe I can win and that is an important step.
"He is the favorite, but why can't tomorrow be my day?"