Smartphones with built -in sensors and applications are being used as measurement tools in physiesexperiments and teaching.In this paper, the pressure sensor of a smartphone with a physical experimentapplication is used to measure the gas pressure at different depths in the swimming pool, and the localgravitational aceeleration is ealeulated by $tevin's Law,which is simple and feasible and has high measuremenaeeuracy.The experimental method is simple and feasible, and the measurement accuraey is high,.Carrying outphysies experiments and teaching based on smartphones can help stimulate students*interest in learning.reduce experimental costs , expand the experimental site , popularize physies knowledge, and improve scientificliteraey.