目的：探讨胎儿外耳的产前超声观察。方法：随机选择11～14孕周、16～20孕周、24～28孕周、32～36孕周的胎儿400例，应用产前超声多切面、多角度观察胎儿双侧外耳的情况，总结超声扫查胎儿外耳的显示率、最佳时期、探查切面。结果：胎儿外耳的显示例数与孕周呈负相关（r=-0.994，P=0.006），随着孕周的增加外耳显示率降低，11～14孕周胎儿外耳的显示率最高，达100%， 32～36孕周最低；11～14孕周以乳突切面冠状位扫查和经枕骨大孔切面冠状位扫查显示率最高，其余孕周以左右颞骨旁矢状切面最易探查胎儿外耳，经乳突切面冠状位、经枕骨大孔切面冠状位和左、右颞骨旁矢状切面外耳获取数与孕周呈负相关，回归方程分别为：Y=242.239-5.674X（r=0.938，P=0.018）；Y=242.092-5.547X（r=0.944，P=0.016）；Y=194.375-1.392X（r=0.605，P=0.021）。从外耳轮廓获取数看，16～20孕周及24～28孕周最能观察出胎儿耳廓形态，而11～14孕周胎儿显示差，但各孕周胎儿耳廓形态总获取率比较，χ2=24.00，P=0.293。结论：不同孕周产前超声对胎儿外耳的显示率不同，以11～14孕周胎儿外耳的显示率最高，随着孕周增加，显示率下降。

 Objective: To explore the diagnosis value of fetal external ears by using ultrasound. Methods: Of 400 fetuses, each 100 cases were selected randomly during gestational 11～14 weeks, 16～20 weeks, 24～28 weeks and 32～36 weeks. Bilateral external ears were observed by using the multi-views and multi-angles of prenatal ultrasonography. To summarize the display rate, the best time and scan sections of ultrasound. Results: The fetal external ear was negatively correlated with gestational age(r=-0.994, P=0.006). With the increasing of gestational age, external ear acquisition rate was showed a downward trend. During gestational 11～14 weeks, it was showed the highest rate, and up to 100%, and the its lowest age was during gestational 32～36 weeks. The mastoid section coronal scan and foramen magnum coronal scan were the best sections during gestational 11～14 weeks of gestation. The left or right temporal parasagittal plane was the best sections to observe the morphology of fetal external ears. The mastoid section coronal scan, foramen magnum coronal scan and left or right temporal parasagittal plane was negatively correlated with gestational age, regression equation: Y=242.239-5.674X(r=0.938, P=0.018); Y=242.092-5.547X(r=0.944, P=0.016); Y=194.375-1.392X(r=0.605, P=0.021). According to the number of morphology the fetal external ear, gestational 16～20 weeks and gestational 24～28 weeks was the best period. Gestational 11～14 weeks display difference. Comparison of the total acquisition rate of fetal ear morphology in different gestational weeks, χ2=24.00, P=0.293. Conclusion: In different gestational weeks, the display rate of the fetal external ear is different, gestational 11～14 weeks is the highest in the display rate of the external ear.