The purpose of study is to investigate the structure of soot layer and evolutionary mechanisms of its deposition/regeneration process when applying five ash loadings in CDPF. The mechanisms can be used to reveal the principle of dual-layer filtration technology and lay the proper foundation for making advanced regeneration strategies to save energy and improve efficiency. The characterization of soot layer structure was analyzed by 2-D laser displacement sensor, pressure sensor and scanning electron microscope ( SEM). The deposition process could be divided into four stages. The shift value of particle layer thickness to start the last stage was about 20 mu m. With the ash amounts increasing, the initial pressure drops increased from 1260 Pa to 4550 Pa and the time-consuming in the first three deposition stages reduced from 250 s to 0 s. The mechanism of 2 g/L ash condition was similar to the dual-layer technology. The regeneration process could be divided into three stages. The irregular soot layer scallops were found in the middle of the 2nd regeneration stage. The "back diffusion" of micro-concentration oxygen molecules caused by catalyst could reduce the beginning temperature from 525 degrees C to 500 degrees C. With the ash amounts increasing from 0 g/L to 8 g/L, the duration time of II-regeneration stage gradually reduced from 3000 s to 0 s. The ash particles could act as oxygen carrier and have a catalytic effect on soot layer. The ash layer could absorb more thermal energy and have higher heat storage capacity.