In the more than 20 years after 1666, Newton made unremitting efforts to improve and perfect his calculus theory, and successively completed three calculus papers: Analysis by Using Infinite Equations (abbreviated as 1669) and Flow Method and Infinite Series (abbreviated as "Flow Method", 65438). They reflect the development process of Newton's calculus theory. However, Newton's paper on calculus was not published in time, and the public expression of his calculus theory first appeared in the book Mathematical Principles of Natural Philosophy published in 1687. Therefore, Principle has also become an epoch-making work in the history of mathematics.