Abstract
In this paper, some counter-examples are given to analyze deeply several common easily confused basic concepts and theories in unary function calculus. Through the examples, it can seen that we must truly understand the basic concepts of advanced mathematics. In order to learn higher mathematics better; it needs us to have a deep understanding about the concept in unary function calculus. In this paper, a number of counter-examples are given to intensify these basic concepts and theories, and the authors gives some explanations for the concept of several common mistakes.