Simple harmonic plane-wave is an important content of 〈〈College Physics〉〉 course which is a required course for the students of science and engineering specialties. It may he not easy for students to deeply understand the potential energy during the study of the simple harmonic plane-wave. This paper proposes a very simple method of analyzing and deriving the potential energy, by using the transmission mechanism and characteristics of the elastic wave. This method does not involve the physical quantities that are unfamiliar to students, and...