The present study investigated the effect of correcting perfectionist cognitive bias on students' anxiety, procrastination, distress tolerance, and obsessive beliefs. The present study was a quasi-experimental study with a pre-test-post-test design with a control group. The statistical population of this study includes 200 male and female students from Azad, Applied Science and Payame Noor universities in Dashtestan. Students ranged in age from 20 to 31 years. Out of 200 people who received the perfectionism questionnaire, in the next stage, 127 students who received a score above 90 on the perfectionism scale were identified and 38 of them were randomly selected. Then, using random assignment method, they were divided into experimental and control groups. After identifying the members of the experimental and control groups, all individuals completed questionnaires on anxiety, procrastination, distress tolerance, and obsessive beliefs. Then, using dot-prob software, the perfectionist cognitive bias of the experimental group members was corrected. Then, to perform cognitive bias correction for two months and 8 weeks, Dot-probe software was used every week on the experimental group one by one (That is, once a week, cognitive bias correction test was taken from 19 subjects in the experimental group). After 8 sessions on the experimental group, Dot-prob software was used again to test the cognitive bias in 38 people and then all of them filled out the questionnaires of procrastination, perfectionism, anxiety tolerance, anxiety and obsessive beliefs. The results of the study show the effect of correcting perfectionist bias to reduce perfectionism in students. In general, there is a significant difference between worrying about mistakes, personal criteria and perfectionism in the experimental and control groups in pre-test and post-test at the level of 0.01. Also, regarding the effect of correcting perfectionist bias in reducing students' anxiety, the results indicate tha