Abstract: DNC and ENC are the two most important data model in digital chart,while ENC is the current international standard of digital chart.With the vast amounts of existing DNC data,it is best way to use them by converting them automatically from DNC to ENC;however,there is no satisfied method from home and abroad.So,with the in-depth analysis on the models of DNC and ENC,mapping relationship of feature and attribute between DNC and ENC is built up in this paper,as well as mapping relationship of topology and spatial geometry,each section followed by mapping flow.With this method,we convert DNC data to ENC automatically and efficiently.Compared with Caris HPD,the best software to covert DNC to ENC nowadays,it is proved that the method in this paper had a much better performance in feature convert efficiency and effect.