High-precision large-scale multi-beam topographic data was edited carefully and used to plot submarine geomorphic shadow graph finally. The fine tectonic features of accretionary wedges and developing patterns of the minisize trapped basins at middle part of Manila Subduction Zone were discussed deeply associating with a seismic profile crossing the study area collected before. Multiple long and narrow minisize trapped basins were identified in lower tectonic zone of accretionary wedge. After analyzing the planar break feature and its deep stress status, we proved that the change of tectonic features from lower tectonic zone to top of the wedge was corresponding to a complete developing process of the minisize trapped basin, that is, from accretion and break stage at start to trap and basin formation in middle stage, extrusion and extinction during late stage, and elevation and nappe stage at last. A new type of developing pattern for accretionary wedges was disclosed during the process and the essence of it was manifested to be the expression of compressive stress on sea floor which was produced by subduction activities of deep plate.