Tsai, speaking to reporters after a national security meeting, said China's influence operations included attempts to interfere with elections and fake news campaigns.
She did not detail specific incidents but said Taiwan's national security agencies would be finding ways to tackle China's moves.
Tsai said Taiwan would deter military aggression in the Taiwan strait, vowing to boost defense capabilities, including upgrading military equipment and the recently launched program to build submarines locally.
"The Chinese Communist Party continues to demonstrate provocative actions in the Taiwan Strait, destroying the status quo across the Taiwan Strait," Tsai said.
Her comments follow a spike in cross-strait tensions last month when China's military staged extensive drills with warships, bombers and reconnaissance aircraft around the island.
Taiwan scrambled jets to monitor the drills, which a senior U.S. official at the time described as "coercion" and a threat to regional stability.
Beijing suspects Tsai is pushing for the island's formal independence and has steadily stepped up political and military pressure.
Any formal independence move is a red line for China, which has never renounced the use of force to bring Taiwan under its control.
Tsai has says she wants to maintain the status quo with China but will defend Taiwan's security and democracy.
The U.S. House of Representatives this week unanimously backed legislation supporting Taiwan as members of the U.S. Congress push for a sharper approach to relations with Beijing.