His major fields of study were Mongolian history, literature, and also Mongolian maps. He not only made a number of invaluable contributions in the academic field, but also edited several popular books on Mongolian history and culture, for example Ein Volk sucht seine Geschichte. He also published several books on Mongolian epics, proverbs, and folk tales.
He worked extensively on the Epic of King Gesar and other epics circulating in Mongolia. In 1978, he initiated a project for the study of epics. Also, with the help of Heissig, the five-volume series "Folklore mongol" by B. Rinchen was published between 1960–1972, followed by a 13-volume series of epics, Mongolische Epen by Nicholas Poppe. His scientific research work has been acknowledged by elections into various learned societies i.a. he was elected foreign member of the Mongolian Academy of Sciences which is the highest scientific honour in Mongolia. (Source Accessed Apr 2, 2021)