Helmholtz Coils are widely used in scientific research and industrial fields,and studying its magnetic field distribution is an important part of university physics experiments.The article uses the smartphone’s built- in magnetometer and physics experiment application (phyphox)to quantitatively measure the current-carrying Helmholtz coils’central axiscentral radial and three-dimensional magnetic field distribution.Comparison of experimental measurement results with theoretical calculations, which is consistent and the measurement accuracy is within the acceptable range,which confirms the feasibility of the method.The introduction of smar phones as sensors in traditional university physics experiments can not only reduce the cost of experiments,but also stimulate interest in learning and enhance students’desire to explore.