High-precision cold atomic interferometry requires a large flux of cold atomic groups, the length of 2D-MOT largely influences the number of cold atomic clusters in the 3D-MOT flux.The longer the 2D-MOT length, the longer the interaction of the atoms with the light field, so that the trajectory of the atom impinges on the inlet of the differential pump tube so that its divergence is small enough to reach the tube, but the length of 2D-MOT is not the longer,the better.There are two reasons for this: first, higher atomic flux and faster atoms are trapped as the length of 2D-MOT increases, resulting in an increase in the number of collisions between lateral radicals.Second, the average speed in the atomic beam increases.Above an optimum MOT length every increase in length will only add faster atoms to the beam, thus increasing the value for the mean velocity.In summary, choosing the best 2D-MOT length plays a key role in getting the number of cold radicals entering 3D-MOT.In this paper, through mathematical modeling and finite element analysis,2D-MOT race-track anti-Helmholtz coils are numerically calculated.Analyzing the distribution of zero magnetic field for coils of different lengths and zero drift and magnetic field gradient changes caused by the error of asymmetrical coil position, the number of uniform turns and parallelism in the process of processing and assembly.The result provides reliable theoretical guidance for the design and manufacture of the magnetic field system of 2D-MOT high-precision cold-atom interferometers. © 2019 SPIE.