Abstract:In order to objective detect the state of dental pulp vitality,the technology of laser induled fluorescence was used,base on the principle of the teeth can excited the fluorescence in the short wavelength source irradiation,and have close relate between the number of fluorescence and the dental pulp vitality.Designed the device which dental pulp fluorescence was detected,analyze the principle how to have the fluorescence,and the distance parameter design between the inputoutput fiber and the teeth,the circiut of detect and gather fluorescence signal was designed,through experiment,analyze the influence factor of the teeth pulp fluorescence strength.