Federer became the first three-time winner in Doha, following titles in 2005 and 2006.
"It is a great start to the new season," Federer told the 8,000 fans at Khalifa Tennis Complex. "I felt great all week here. I controlled the game from the first set and did well in the second, too."
When asked about his chances at the Australian Open this month, a smiling Federer said: "I am not ready now. I will be when I get there. But obviously, the wins here will help me build my rhythm [in Australia]."
Davydenko, who beat top-ranked Rafael Nadal in the semifinals and also hadn't dropped a set going into the final, was attempting to become the first player to beat Nadal and Federer in the same tournament three times. He did it in Doha a year ago and at the 2009 ATP Finals.
The fourth-seeded Russian looked overmatched from the start and fell to his 15th loss in 17 matches against second-seeded Federer.
"He played very well. I have played him so many times and I know he was fast today. He gave me no chance," Davydenko said. "If I tried to play baseline, he was too fast. When he played backhand, then he was too good. I think if he can hold his form like this, he can be No. 1 again.
"I did not play bad. My tennis is good. It's just that Federer did not give me a chance. Today, I had no chance."
Federer broke Davydenko in Game 2 by producing a deft drop shot after the Russian hit a couple of shots into the net. Davydenko valiantly saved seven set points on serve in the eighth game, but in the next game Federer easily held serve to close the first set.
In the second, Davydenko held serve until the ninth game when Federer charged to the net twice to fetch winners for the break.
Federer then served out for his 67th career title, fourth-best in the Open era after Jimmy Connors (109), Ivan Lendl (94) and John McEnroe (77).
"I was flawless today," Federer said. "I have served well all week. If I keep playing like this, I have a chance [to be No. 1]. I got many good matches here and in Abu Dhabi."
Last weekend in Abu Dhabi, Federer lost to Nadal in an exhibition tournament.