Objective:The aim of this study was to assess the effect of different toothbrushing duration time on removing dental plaque. Methods:27 cases were randomly selected. The duration time of toothbrushing for each one of the four quadrants of each case was decided randomly, which contained 10sec, 20sec, 40sec and 60sec. Each case was required to brush their teeth with vertical method and assessed using Modification of Quigley & Hein Plaque index. Plaque index was recorded before and after toothbrushing. Results:The rate of plaque reduction of different toothbrushing duration time was 21.29%,24.86%,25.92%,25.19% respectively (p<0.05), but there was no significant difference in removing dental plaque among 15, 20, 40 and 60 seconds (p>0.05). Conclusion:The study suggested that it was effective enough to remove dental plaque by vertical method in 1 minute.