The 21st century is a time of new change and varied cultural changes. These changes are implemented independently of the human mind, society, social customs, and research techniques using the reason and logic expressed in the existence of human nature. From the viewpoint of postmodern thinkers, the existence and properties of natural reality act logically independently of human beings on the basis of realism.Christian apologetics is under paralysis in postmodern era, but apology is a dialectic of the Christian gospel for the purpose of evangelism. In this respect, this paper focuses on evangelism and missions in order to proactively reveal the truth of Christianity and search for a defense mechanism that can effectively counter various misunderstandings about Christianity. It is clear nowadays that the apostasy of Christianity is directly related to the proclamation of the gospel. Therefore, even if the times and cultural circumstances change, we should keep the Christian values based on the environment that the truth of the gospel does not change, and use apologetics only for the preaching of the Christian gospel, so that biblical doctrine can be believed and followed correctly.