Abstract: Both of northern part of the Yap Trench and the southwestern end of the Mariana Trench are affected by the subduction of Caroline Island Ridge, but the geophysical characteristics for these two regions show significant differences. Based on a comprehensive analysis including the submarine topography, gravity anomaly, seismic activity and stress field, this study compared the geophysical characteristics of these two regions. Results shows that, ①There is a structural belt of horsts and grabens at the outer edge of the northern part of the Yap Trench. The depth of the southwestern end of the Mariana Trench where the Caroline Island Ridge being subducted is shallower than that of the surrounding area. And a concave angle is formed at the subduction front of the Ridge. ②The high Bouguer anomaly in the northern part of the Yap Arc and the southwestern end of the Mariana Arc corresponding to the Caroline Island Ridge suggest that the strong tectonic erosion may lead to the loss of volcanic arc crust, which indicates that high-density materials upwell underlie the arc. ③The seismic activities of the northern part of the Yap subduction zone and the southwestern end of the Mariana subduction zone are weak, and there is a lack of high magnitude earthquakes, suggesting that the Caroline Island Ridge subduction inhibits the tectonic activity of the subduction zone. There are a few moderate earthquakes in the southwestern end of the Mariana subduction zone, indicating that the slab subduction depth in the region is deeper than that in the northern part of the Yap subduction zone. ④The earthquakes at the southwestern end of the Mariana subduction zone have more strike-slip components, which are related to the oblique subduction of the Caroline plate and the oblique collision of the Caroline Island Ridge. ⑤The subduction angle of the Caroline Island Ridge relative to the trench strike is the key factor for leading to the differences in geophysical characteristics between the northern part of the Yap subduction zone and the southwestern end of the Mariana subduction zone.