A simple sound velocity measurement device based on smartphone is designed to take accuratemeasurements of the sound velocity in different propagation media using the standing wave method. In theexperiment ,the FreqCounter APP on the smartphone is used to generate a single frequency acoustic signal.TheDaTuner APP,on the other hand, is used to detect in real-time the frequency and intensity of the acousticwave.By measuring the distance between adjacent antinodes or nodes , the sound velocity can be calculated according to the relationship among the frequency, the sound velocity, and the distance between adjacentantinodes.The sound velocity values obtained from the experiments are in good agreement with the theoreticavalues.