本文綜述了当前对莫霍界面性貭的学說,列举了相变学說所遇到的困难。根据新近地震面波和体波所获得有关地幔頂部速度分布的资料,进一步探討了莫霍界面的性貭,所得的結論为: (1)大陆和海洋的莫霍界面都不是相变面; (2)地幔頂部沿深度方向不可能由均勻物貭所組成,低速带的形成与物貭的組成有关; (3)大陆和海洋的地幔頂部,其差异主要在于低速带頂面位置的不同,大陆的較深,海洋的較浅; (4)根据放射性含量的測定,組成地幔頂部的物貭可能是榴輝岩与其他超基性岩石的混合物,其速度受溫度的影响不大。 This article summarizes the current doctrine of Moho interface properties and lists the difficulties encountered in the theory of phase transition. According to the data about velocity distribution of the top of the mantle obtained by recent seismic surface waves and body waves, the properties of the Moho interface are further discussed. The conclusions obtained are as follows: (1) Both the Moho and the ocean are not phase transition surfaces; 2) The top of the mantle can not be composed of uniform objects in the depth direction, and the formation of low-speed zones is related to the composition of objects. (3) The top of the mantle of the continents and oceans is mainly caused by the difference of the location of the top of the low- (4) According to the determination of radioactive content, the material forming the top of the mantle may be a mixture of eclogites and other ultrabasic rocks whose velocity is not affected by the temperature.