The pigment electrophoresis dispersion has been the widely used system. It is, however, worth of attention if molecular dye, instead of pigment, can be used in the display of electronic paper. By carefully selecting the structure of dyes, especially the metal complex dyes, and studying the properties of the prototype display. It was found there are about 15 dyes electrophoresis and some dyes display well. The dyes ink with good stability during electrophoresis when the electrode was protected, while the response time is about 300 ms, and the concentration is an important factor on the display optic density. The displaying principle of dye ink was studied too.