A new photochromic diarylethene bearing naphthyl unit was synthesized efficiently. Its photochromic properties and the fluorescence property were examined in hexane solution and in PMMA film. The concentration effect in hexane solution was investigated also. The results indicated that the photochromic diarylethene have good photochromic property and exhibit remarkable fluorescence switching property and when the concentration at 2 x 10(-5) mol/L the fluorescence peak have the maximum.