To analyze the effect of topical anesthetics in taking dental X-ray film.300 patients, who needed to take dental X-ray photography of maxillary or mandibular molar were randomly assigned to 3 groups. Bisecting angle technique was used to take the film. Before taking the X-ray, the throats of the patients in Group I were treated by 1% dyclonine spraying anesthesia, Group II were treated by FRILJET local cryoanesthesia and pulp vitality test agent, and Group III were set as control. The anesthesia efficiency and imagine quality of the dental films were evaluated, and the anesthetic time was recorded. The data was analyzed with ANOVA and Chi-square test using SPSS12.2 software package.The anesthesia efficiency was 99% in group I, 98% in Group II, and 62% in Group III. The imagine quality in Group I and II was higher than that in Group III. For both anesthesia efficiency and imagine quality, there was no significant difference between Group I and Group II, but there was significant difference between Group I and Group III, and between Group II and Group III (P<0.01).Significant difference of anesthetic time was showed between Group I and Group II . Compared with Group II, longer time(4 minutes) was needed in Group I to show the anesthetic effect, and it lasted longer for 21.62+/-3.54 minutes; while in Group II, the anesthetic effect lasted shorter, only for 2.07+/-1.22 minutes, but it developed immediately.The use of local anesthetics improves the accuracy, quality, and success rate in taking dental X-ray films.