分析了控制磁粉检验系统综合性能的标准环形试块的作用机理。首先建立了计算漏磁场的简化数学模型，然后解标量磁位的二维拉普拉斯方程，求出被磁化的环形试块上通孔产生的漏磁场，计算了环形试块表面的磁粉受力情况。理论分析表明，① 通孔缺陷中心处漏磁场切向分量值最大，垂直分量值为0。② 磁粉受力的切向分量在通孔缺陷中心两侧各有一个大小相等方向相反的极值。③ 当通孔直径不变时，随通孔深度增加，其表面处漏磁场和磁粉受力的切向分量均迅速下降。④ 当通孔距表面距离不变时，随通孔直径减小，其表面处漏磁场和磁粉受力的切向分量均迅速减小。

The mechanism of annulus reference block measuring integrated properties of magnetic particle testing was analyzed. A simplified mathematical model of magnetic flux leakage (MFL) was developed. The MFL of through hole in the annulus reference block was calculated by solving Laplace equation of scalar magnetic potential. The stress of magnetic particle on the annulus reference block was also calculated. Theoretical analysis indicates that ① the tangential component value of MFL on the center of through hole is maximum, and the normal component value is minimum. ② At the both sides of through hole center, the tangential component of magnetic partical stress is equivalent in value but opposite in direction. ③ Under the condition of constant diameter of through hole, with the increasing of through hole depth, the tangential component of surface MFL and magnetic partical stress both decrease rapidly. ④ Under the condition of constant depth of through hole, with the decreasing of through hole diameter, the tangential component of surface MFL and mgnetic partical stress both decrease rapidly.