The built-in coil heating will affect the magnetorheological fluid viscosity,and the built-in coil will lead to the difficulty in installation and disassembly.In order to solve the above problems,the structure design of the external coil magnetorheological fluid shock absorber was studied;the influences of different cylinder materials,coil layout and structural parameters on the magnetic induction intensity at the gap were analyzed through simulation.The results show that the magnetic induction intensity at the gap increases gradually with the increase of current,but it cannot increase indefinitely due to the influence of magnetic saturation intensity;the coil external magnetorheological fluid shock absorber should use the single coil model with the widest slot;as the gap increases,the magnetic induction intensity at the gap decreases.