This paper describes the observed results of short-time pellet ablation based on CCD application during the multi-pellet fuelling experiment in the HL-1M tokamak, introduces a characteristic trigger mode, that is, Ha radiation signal emitting from pellet itself to trigger CCD camera. The experiment proves that a lot of photos can be taken through this arrangement and CCD camera is successfully applied to pellet ablation process investigation. Through photos processing and analysis, the structure on different plasma positions, dimension and space Ha emission profile of ablation cloud are obtained, therefore the CCD diagnosis means not only makes pellet fuelling understand deeply,but also may promote the transient &high-speed process research in the field of military and engineering.