Background Cognitive behavioral therapy （CBT） is a widely used and empirically supported psychotherapy method. In recent years， the localization of CBT related to culture has received increasing attention from Chinese scholars. However， there is still a lack of systematic research on the localization of CBT using idioms as materials.Objective To explore whether idioms reflect the mutual influence between the two core therapeutic elements of CBT （cognition and emotion） and to use them as CBT treatment tools among college students， so as to provide references for the localization of CBT.Methods Using the Xinhua Idiom Dictionary （second edition） published by the Commercial Press， a three-round manual screening method was used to select idioms that reflected the mutual influence between cognition and emotion in CBT. Based on the selected idioms， a survey questionnaire titled "survey on idiom understanding level" was developed. From August to October， 2022， stratified sampling was conducted among college students from different majors and universities， and 815 valid questionnaires were obtained through the Questionnaire Star platform. By analyzing the understanding of each idiom among college students， idioms that could be used as CBT treatment tools were identified.Results In the Xinhua Idiom Dictionary （second edition）， there were 13 idioms that reflected the influence of cognition on emotion and 5 idioms that reflected the influence of emotion on cognition. 12 idioms could be used as CBT treatment tools， including 8 idioms that reflected the influence of cognition on emotion and 4 idioms that reflected the influence of emotion on cognition.Conclusion There may be idioms that reflect the mutual influence between the two core therapeutic elements of CBT （cognition and emotion） and these idioms can be attempted as a therapeutic tool for CBT among college students.