中国伊斯兰教
From 1917, Chen began to work on history of Christianity in China, and later published his name-earning book "Research of Arkaguns in Yuan Dynasty" (). Arkagun is the name given to Christians in Yuan Dynasty. Subsequently, he published several books about the spreading of Manichaeism, Zoroastrianism and Islam in China. Chen also paid great attention to collation work on Code of Yuan Dynasty ().