This year's 10-day live-fire Han Guang drills are the longest yet and follow the delivery of a range of new weaponry from tanks to unmanned waterborne drones.
The drills in Taiwan come as regional tensions and harassment by China and its People's Liberation Army are increasing.
China claims Taiwan as its territory to be annexed by force if necessary, while the vast majority of Taiwanese wish to become fully independent or retain their status of de facto independence.
The drills began with exercises to counter the actions of Chinese Coast Guard and maritime militia ships that have been harassing Taiwanese ships around offshore island groups close to the Chinese coast, the defence ministry said.
Concerns are that China could launch an invasion under the guise of petty harassment, and the drills will include fortifying ports and possible Chinese landing points on an island lying 160km off the Chinese coast.
The drills will later focus on simulated anti-landing exercises, with regular forces from all the services backed up by 22,000 reservists, the ministry said.
Exercises would continue around the clock for 10 days under realistic conditions taking into account all possibilities, the ministry said, in a possible attempt to counter criticisms that past exercises have veered on the performative.
The ministry called on the public to show patience with any disruptions to flights or traffic and not to believe false information distributed about the exercises.
China responded to the exercises' announcement in typically acerbic fashion.
"The Han Guang exercise is nothing but a bluffing and self-deceiving trick by the DPP authorities, attempting to bind the Taiwanese people to the Taiwan independence cart and harm Taiwan for the selfish interests of one party," Chinese defence ministry spokesman Colonel Jiang Bing said at a news conference on Tuesday.
The DPP stands for Taiwan's independence-leading ruling Democratic Progressive Party.
"No matter how they perform or what weapons they use, they cannot resist the PLA's anti-independence sword and the historical trend of the motherland's inevitable reunification," Jiang said.
