Abstract: The Helmholtz coil is widely used in the device for dozens of Tesla quasi static pulsed magnetic field generation. Based on the quasi-static pulse magnetic field generator for magnetically applied pressure-shear experiments, the thermal and stress of the Helmholtz coil are researched by means of the finite element software ANSYS. The calculated results show that the maximum stress is about 0.5 GPa in the coil pair and 0.2 GPa in the copper wires, and that the displacement of the coil wire is less than 0.05 mm and that the temperature increase in the coil pair is about 150 ℃ when a discharge current flows through the magnet coil pair with a peak current of 14.37 kA and a rising time of 1.34 ms, which can produce 10.7 T magnetic field in the center of the coil pair. These calculated results provide a basis for the optimization design and reinforcement of the coil structure, the copper wire with a tensile strength of 0.5 GPa and insulating layer which can withstand temperature more than 200 ℃ is chosen as the coil wire, and that the zylon fiber with a tensile strength of 5.8 GPa is chosen as the reinforcement around the copper wire, and the corresponding Helmholtz coil structure is designed. This coil pair is used for discharging test and the results show that the coil pair is strong and reliable, and it can be repeatedly used in case of meeting design parameters.