Fellow Jamaican Warren Weir improved on his Olympic bronze by taking silver in a personal best 19.79 from lane eight while Curtis Mitchell won bronze for the United States in 20.04, just preventing another Jamaican podium sweep as he beat Nickel Ashmeade by a hundredth of a second.
Bolt insisted that the win was as easy as he made it look.
"There was not any pressure. I went out there, focused, I was ready to go. It was just about running a good corner, and that's what I did," he said.
"I'm happy with what I did and happy to have it done. One shoot, back to back now, so I'm happy."
Britain's Adam Gemili came off the bend in third place but faded to finish fifth, a superb showing from a runner who is still just 19 years old.
Yet the young British star will no doubt be bitterly disappointed that he failed to match or better the 19.98 he ran in the semi-finals, a time that would have secured bronze.
Bolt, the world record holder with his 19.19 from Berlin four years ago, won the 100 metres last weekend having completed the sprint double twice at the Olympics and also in the 2009 world championships.
He was always in command from lane four on Saturday and halfway round the opening bend he loomed over diminutive British teenager Adam Gemili in lane five like an ocean-going liner swamping a dinghy, before disappearing into the distance.
After a slow start to the season when he was hampered by injury, Bolt has been on an upward curve in the last few weeks and his 19.73 in Paris six weeks ago was the fastest time of the year before Saturday's race.
American Tyson Gay, who ran 19.74 in June and was the last man to beat Bolt in a global 200 when he won the 2007 world championships, was unable to challenge him again in Moscow having failed a doping test.
On Sunday Bolt will hope to complete a hat-trick in the 4x100m relay on Sunday, when gold would draw him level as the all-time most decorated athlete in World Championship history: he would be alongside American trio Allyson Felix, Carl Lewis and Michael Johnson with eight world titles, but he says that prospect does not worry make any extra pressure.
"No, I'm not worried about that. For me I have made my legend start, that was the key," he said.
"Now, I'm just adding the greatness. I'm just going to continue trying to win championships and then look forward to next Olympics.
"I've discussed it with my coach about what we should do. I was telling him 'Coach we should relax next season'.
"But my coach said 'we need just to continue pushing, pushing because it's good to follow up every year with a good year so your body is used to it.'
"So we're just going to continue working hard, pushing myself, continue going to the championships day by day and hopefully everything will work out."