Periodic geography is a borderline science between periodic science and geography. At present, scientists abroad are going deeper and deeper into the study of periodic science and periodic geography continually, while in our country, periodic geography is in an embryonic stage, and the geography is in the embryonic stage, it is necessary to make further inquiry.
This article is trying to make an exposition of periodic geography——the cause of formation of periods and the basic theory of this newly developing subject of human geography.