The state has imposed Atheism on the population. Only about 10% of the population professes any faith, mostly Buddhism. Taoism, Islam and Christianity are the next largest.
This depends where.
Christianity
Christianity was the main religion back in the 1800's because of all the settler's arriving who were big Christians.
Donald E. MacInnis has written: 'Religion in China today' -- subject(s): Religion
Lutheran Christianity.
F. W. S. O'Neill has written: 'The quest for God in China' -- subject(s): Religion
Milton M. Chiu has written: 'The Tao of Chinese religion' -- subject(s): China, Religion, Tao
Their was no main religion, anyone could believe or not believe in anything.
mount. Everest and another one :S
Mainly catholicism islam and christianity
David Aikman has written: 'Love China Today' 'A Man of Faith' 'When the almond tree blossoms' -- subject(s): Fiction, Politics and government, Totalitarianism 'A man of faith' -- subject(s): Accessible book, Church and state, Religion 'Ionic relations of marine algae'
there was no popular religion at that time in Arab, but thousands different small religions. Mostly idol worshippers.