Gait recognition has been of great importance for disease diagnosis, rehabilitation assessment, as well as personal identification. Conventional gait analysis generally has to rely heavily on complex, expensive data acquisition and computing apparatus. To significantly simplify the evaluation process the mobile phone, which is one of the most indispensable electronic media in human daily life, was adopted as a pervasive tool for gait study, by using its digital imaging recording and analysis function. The basic procedure to record and quantify the video of human gait was illustrated and demonstrated through conceptual experiments. Potential applications were discussed. Some fundamental and practical issues raised in such flexible technology were pointed out. This method is expected to be widely used in future human analysis.