Djokovic has won the tournament at the Olympic tennis stadium in Beijing for the past four years and racked up 29 straight wins in the Chinese capital.
Nadal, despite his fine revenge win of Fabio Fognini in the semifinals, was never able to get on terms with the world number one and his overall career lead over the Serb has been trimmed to 23-22, with seven of the last eight encounters going the way of Djokovic.
The 6-2 6-2 scoreline was unflattering to the Spaniard who detained Djokovic on court for 91 minutes, his longest match of the week, but the result was never seriously in doubt from the moment Nadal was broken in the very first game.
He also needed the attention of the trainer in the second set and was broken twice more in sliding to defeat against the unstoppable Djokovic.
Consolation for Nadal, who was seeking his fourth title of the year, but no grand slams, is that he has moved to sixth place in the race to qualify for the ATP World Tour Finals in London next month.
Djokovic will start as undoubted favorite to round off his year by defending that title, having won three of the four slams and eight tournaments to date in compiling a 68-5 record in 2015.
It is on a statistical par with his stellar 2011 season when he compiled a 70-6 record and he can improve it in this week's Shanghai Masters, where Nadal also competes.
He was delighted by his play in Beijing, winning a sixth title on a court he has made his own in recent years.
"I played a great tournament overall and continued playing well today. Rafa and I have played 45 times and I hope that continues," the 28-year-old told the ATP Tour official website.
"The scoreline, especially in the first set, doesn't indicate the real battle that we had on the court," he added.
Meanwhile, Switzerland's Stan Wawrinka, who beat Djokovic in the final of this year's French Open, captured his fourth title of the season as he won the Japan Open in Tokyo.
He beat unseeded Frenchman Benoit Paire 6-2 6-4 in just over an hour at the venue to be used for the tennis events at the 2020 Olympic Games.