Wrong pen grip posture accounts for a very large proportion of pen grip posture in adults. In order to scientifically explore the problem of wrong pen grip posture in adults, this paper takes a certain number of college students as the research object and investigates their pen grip posture. Then, the paper points out several typical wrong pen grip postures and makes a mechanical analysis of the correct pen grip posture. In addition, considering the relatively weak finger strength of most children, the paper focuses on analysing the causes of wrong pen grip postures in adults from the root, and discusses the possible effects of wrong pen grip postures in various aspects. Finally, these analyses are used to raise awareness of the pen grip posture and help educators to change the traditional educational approach in pen grip posture.