The eta-type tectonic system was suggested by academician Li Si-guan more than 70 years ago, and two great eta-type tectonic systems have been described: one is located in Qinhai-Xizang (Tibet)-Yunan-Burma-Indonesia (QXYBI), and another is western part of North America (WNA). Recently they have been applied to the earthquake prediction successfully. In this paper a brief introduction is concerned to the prediction of MS 8. 3 Wenchuan earthquake by Huang Xiangning based on the QXYBI eta-type tectonic system, and also to the prediction of MS 7. 5 Mexico earthquake by author according to the WNA eta-type tectonic system. The time intervals (about 53~54 years) among super-great earthquakes occurred in the same eta-type tectonic system demonstrate clear orderliness related to 3 times of astronomical Saros Period. Thus, it is clear that the modern seismic activity of eta-type tectonic systems is stimulated by the astronomical factors, and this character is favorable for the prediction of great earthquake in future.