The sound velocity in air varies with temperature. In this paper a finite length straight pipe is used to measure the sound velocity, and mobile APP is adopted as a transmitter and a receiver of sound wave. A constant temperature condition is fulfilled in the internal area of the pipe in order to accomplish the sound velocity measurements at different temperature by standing wave method. The relative errors of the measurements maintained to be less than 2%. This home-based experiment proposed in this paper is a prolongation of traditional physical experiments. It can be arranged as an online experiment during special epidemic period. It can also promote the comprehensive quality and the practical innovation abilities of students.