Objective To compare the learning outcomes of Sudoku grid endodontic access opening (SEO) and that of traditional endodontic access opening (TEO) on the training of endodontic access opening skills for undergraduates.Methods Twenty-two undergraduates receiving endodontic access opening training for the first time were selected. The self control experiment was conducted on the students performing SEO and TEO on the artificial teeth and extracted teeth of the first molar, respectively. The time needed for completion of access opening was recorded respectively. The results were then scored according to the standard of endodontic access opening. The statistical analysis was carried out finally.Results On the artificial teeth, the operating time of TEO than SEO was [33.0(26.3, 48.8)] vs [20.0 (12.3, 24.0)]; the score/ time of them was [0.3 (0.2, 0.5)] vs [0.7(0.5, 1.0)]. On the extracted teeth, the operating time of TEO than SEO was [40.0(30.0, 60.0)] vs [24.0 (18.0, 35.0)]; the score/ time of TEO than SEO was [0.2 (0.1, 0.3)] vs [0.4(0.3,0.6)]. All the differences were statistically significant (P<0.05).Conclusions At the initial stage of endodontic access opening skills training,SEO method significantly improves trainees' operant level faster than TEO method