Abstract
In this paper, Biot - Savart formula as the basis for the introduction of the magnetic field solenoid formula. By calculating a real problem, it is proven that the formula is reliable. Magnetic field's computing program is used by computer. Lastly, an axis magnetic field and the spatial magnetic field are calculated, and the result is discussed. And formula for calculating the proceeds can be easily applied to electric equipment in the analysis and design of solenoid magnetic field.
