Williams took just 79 minutes to blitz Sharapova off Centre Court with 13 aces and 29 winners as the five-time Wimbledon champion secured her 18th career win in 20 meetings with her bitter rival.
The 33-year-old American will face Spanish 20th seed Garbine Muguruza on Saturday in her first Wimbledon final since 2012.
It will be her 25th Grand Slam final as she eyes a 21st major title.
"I got a little nervous because it was the semi-finals and it's a long time since I've been this far at Wimbledon. I'm excited to get through," said Williams, who didn't allow Sharapova a single break point.
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"The feeling gets better. It's been a long time since I've been in the final here. It's really cool."
Serena, who extended her winning run at Grand Slams to 27 matches and her 2015 record to 38-1, is just one win away from holding all four major titles at the same time -- a feat she last achieved in 2002-03.
She is also within touching distance of becoming the first woman to win the French Open and Wimbledon back to back since she last achieved that difficult double in 2002.
It was another chastening defeat for Sharapova and, although the Russian world number four is due to return to number two in the rankings next week, the latest instalment of their one-sided rivalry provided further proof of the vast gulf in class.
It was at Wimbledon where the roots of their rivalry took hold in 2004 when Sharapova, then aged just 17, shocked Serena in the final.
Their relationship has since turned increasingly frosty, with both players publicly sniping about Sharapova dating Serena's old boyfriend, the Bulgarian player Grigor Dimitrov.