They were suspected of communicating with a Hong Kong-based representative of the commission, Mirror Media said.
Two sources involved in security matters said that Chang was being investigated. One of the sources said Chang was among several people being investigated by the military and the Investigation Bureau security agency.
One of the sources, who is involved in security planning, said the people being investigated were suspected of being used in "penetration efforts" by Beijing.
Chang, Taiwan's highest-ranking air force general, did not respond to a request for comment but issued a statement in which he said the Mirror Media report was "far-fetched" and harmed him and the military.
He did not say if he had been notified of an investigation but said he would do everything he could to clarify the situation to authorities, when required to.
"I have been a military man for decades. I have always developed a habit of keeping secrets and have not talked about military matters without permission," said Chang, who has not been detained.
A Taiwan defence ministry spokesman did not comment on any investigation and referred Reuters to a statement from the ministry in which it said "intelligence units" of the Chinese Communist Party had been trying to get in touch with top generals "through intermediaries" but no national secrets had been leaked.
The ministry had "actively reinforced anti-espionage education" for soldiers and their families, which it said was "effective in countering infiltration by enemy spies and protecting national security", it said in a statement.
China's defence ministry did not immediately respond to a request for comment.
A spokesman at the National Defense University said Chang's position there has not changed. He declined further comment.
Mirror Media said the Hong Kong-based representative of the Chinese Central Military Commission had travelled to Taiwan where he dined with Chang several times. The representative also organised a trip to Hong Kong for Chang's wife, it said.
Chang, who was deputy defence minister until the end of June, said he had paid for the trip and he always strictly followed rules on secrecy when dining with fellow soldiers and friends.
The investigation comes at a sensitive time in relations between Beijing and Taiwan.
Beijing has ramped up an influence campaign to sway public opinion on the island while its military has been making incursions into Taiwan's air defence identification zone and into waters close to the island.
China has described the missions as necessary to protect its sovereignty and deal with "collusion" between Taipei and Washington.
The United States, which like most countries has no formal diplomatic ties with Taiwan, has watched with alarm the rising tension with Beijing.
(Reporting By Yimou Lee Editing by Robert Birsel) ((firstname.lastname@example.org; +886-2-8729-5122;))