In order to accurately measure and visualize the spatial magnetic field distribution，we designed a visual measurement system of spatial magnetic field based on single chip microcomputer．The system consists of magnetic field data acquisition and storage module，data transmission module and measurement result display module．Firstly，the three-dimensional magnetic induction component of each point in space is measured by Hall magnetic sensor．Then，the data of magnetic induction intensity in a certain area is collected and stored by a single chip microcomputer，and is imported into computer through USB serial port． Finally，the measurement results are displayed by computer，and through data simulation to show the vector distribution of spatial magnetic field intensity，so as to realize the visual measurement and display function of spatial magnetic field．Experimental results show that the accuracy of the magnetic field measurement system is 1 μT，the measuring tange is ± 8 500 μT，and the measurement error is 0． 62%． This visualization measurement system of spatial magnetic field has high precision，wide range，which can visually display the spatial magnetic field distribution，can assist university physics experiments teaching，also can be applied to the measurement of complex and variable magnetic fields．