The delamination wear mechanism of the thermally sprayed coatings was studied by analyzing coatings structural feature and stress distribution on the warm surface, and the influencing factors on the delamination wear were discussed. And the delamination wear mode of coating was developed. The results show that, the thermally sprayed coatings have typical aspect of lamellar structure. There are oxide layers between splats, and there also exist porosity and micro-crack in the coatings. The coating surface was subjected to alternately tensile stress and compression stress caused by normal load and friction force during sliding. In a certain depth below the surface, there exists maximum shear stress. Therefore fatigue damage will take place at subsurface of the coating under alternate stress. The adhesion strength between splats of coating prepared by HVAS is by far lower than casting material because of lamellar structure. And the adhesion strength between splats is further weakened due to the defects (such as porosity and micro-crack) appearing mostly on the boundaries between thin oxide sheets and splats. When the fatigue damage accumulates to a certain value, micro-cracks initiate at the defects between splats. Then these micro-cracks grow, connect, and propagate along the defects between splats. Finally, these cracks shear to the coating surface leading to spallation of the splats, and thus wear debris is generated. By repeating the above process delamination of the coatings will occur. Reducing friction coefficient, increasing coatings hardness and adhesion strength between inter-splats are the basic methods to improve the wear resistance of thermally sprayed coatings. Abstract only; no full-text paper available.