Chang Ya-chung is a Taiwanese political scientist. He founded the Democratic Action Alliance in 2004 and was elected to the National Assembly in 2005, but resigned on the first day to protest the parliament's formation. He later chaired the Chinese Integration Association. Chang subsequently became an active member of the Kuomintang, contesting the party's 2019 presidential primary. He was deemed an ineligible candidate for the party's 2020 leadership election, placing second in the following year.

The 2019 Kuomintang presidential primary was held after 22 May 2019 through a series of nationwide opinion polls in order to determine its nominee for the President of the Republic of China in the 2020 presidential election.