The Serbian showed no mercy against the Spaniard, who was hampered by a foot problem in the second set, as he cruised to a 6-2, 6-2 victory at the National Tennis Centre in the Chinese capital.
"I played a great tournament overall and continued playing well today," Djokovic said at the trophy presentation.
"This definitely has been my most successful tournament in my career. I have won the Australian Open five times but Beijing has been a lucky place for me.
"I keep on coming back here and have very positive memories."
Djokovic has now beaten Nadal in seven of their last eight meetings, dating back to the 2013 China Open, and is on the verge of leveling their head-to-head record.
The pair have played each other 45 times with Nadal, who has struggled with his form and niggling injuries in the past year, hanging on to a 23-22 advantage.
The world number eight took a medical timeout early in the second set when he hurt his right ankle but continued on, despite appearing to be in discomfort.
Djokovic has never been beaten at the China Open, winning 29 matches in a row, and six titles in total. The 28-year-old has now 56 career titles, eight of them this year, including the Australian Open, Wimbledon and US Open grand slam crowns.
"I have to say congratulations to Novak, he's having one of the best seasons in the history of our sport," Nadal said.
"For me, it's also been a very positive week.
"I've been improving every single match and all the matches are good practice for me and especially the victories (because they) are a lot of positive energy for next year."