本文采用添加补偿线圈的方式，对多层密绕直螺线管轴线上的磁场均匀性进行了改进，并根据理论公式，结合Python软件，对直螺线管添加补偿线圈前后的磁感应强度变化曲线进行了仿真模拟. 基于仿真结果，进一步研究了改进后的磁场均匀区间大小与补偿线圈参数、模拟曲线图形之间的变化规律. 发现当补偿线圈匝数确定时，均匀区间大小会随着电流强度的增加先增后减，并且会在曲线图形凸点进出阈值时产生骤升骤降的变化. 在电流强度可以提供的前提下，匝数更少的补偿线圈可以对原磁场均匀性产生更好的延展效果.

The magnetic field uniformity on the axis of a straight solenoid wounded tightly with multilayers is improved by adding compensation coils. According to theoretical formula and combined with Python software,the magnetic induction curve before and after adding compensation coils is simulated. Based on the simulation results,the variation law between the improved uniform interval size of the magnetic field and the compensation coil parameters,the simulation curve graph is further studied. It is found that when the number of turns of the compensation coil is determined,the uniform interval size will increase first and then decrease with the increase of current intensity,and it will suddenly rise and drop when the convex points enter and exit the threshold of the curve graph. Under the premise that the current intensity can be provided,the compensation coil with fewer turns can produce better extension effect on the uniformity of the primary magnetic field.