The Serb's second-round encounter was one of just two matches to take place on Wednesday, as the rest of the schedule at the ATP 500 hard-court event fell victim to heavy rain in the Chinese capital.
Djokovic is going in search of a fifth China Open title in six years as he bids to boost his chances securing the season-end world number one spot.
And, having seen off Guillermo Garcia-Lopez in straight sets in the first round, Djokovic looked like making light work of Canada's Pospisil as he opened up a 3-1 lead in the opening set.
Pospisil never looked like threatening that lead - picking up a total of just three points from Djokovic's four service games - and the Wimbledon champion broke again before the set was up.
The second proved a much tighter affair and Pospisil managed to build a 5-3 advantage over his more illustrious opponent.
However, the shock of going a break down sparked Djokovic into life, and the 27-year-old won the next four games on the bounce to safely book his place in the third round.
"You work all your life and you dream about becoming the number one in the world, the best in what you do," Djokovic said. "It's definitely always the highest priority out there along with winning Grand Slam titles.
"That gives me plenty of motivation. It would mean a lot to me.
"That's why I'm out here in Beijing and Shanghai, competing and trying to get that year-end number one."
In the day's other match, John Isner overcame an early scare to claim a 3-6 7-5 7-6 (6-4) victory over Tommy Robredo.
Two late breaks gave Robredo victory in the first set, before Isner battled back to edge his way into the next round.