利用毕奥-萨伐尔定律，首先分析了单个载流圆线圈在空间任意一点的磁感强度分布的积分表达式，获得了其解析计算结果，并利用Mathematic 描绘了其磁感线分布，同时分析了载流圆线圈所在圆面上磁感分布的特点.进而，基于单个载流圆线圈的结果，讨论了长直螺线管在空间任意一点的磁感分布，通过数值计算分析讨论了其磁场在空间分布的“均匀区”，并利用Mathematic 描绘了其磁感线分布.最后，结合工科“大学物理”和“大学物理实验”中所涉及到的有关问题作了相应的讨论.

The integral expression of magnetic induction distribution by a single current-carrying circular coil at any point is analyzed through Biot-Savart law. The analytical results are obtained and the distribution of magnetic induction lines are described by using Mathematic. The characteristics of magnetic induction distribution on the circular surface，where the current-carrying circular coil is located，are also analyzed. Besides，the magnetic induction distribution of long straight solenoid at any point is discussed by the results of current-carrying circular coil. The“uniform region”of magnetic field distribution is discussed and analyzed by numerical calculation. The distribution of magnetic induction line is described by Mathematica. Finally，the problems related to College Physics and College Physics Experiments are discussed.