Aims: The “bilingual advantage effect” mainly refers to that bilinguals have more advantages on executive functions involved inhibition , shifting and updating , in general , most researchers tend to study the effect of bilingual on the inhibition and shifting which are two distinct components of executive functions . The current study mainly investigated the effect of bilingual on the third component of executive functions , namely working memory updating . The current study also divided working memory updating tasks into single working memory task and conflict working memory task , in order to discuss the bilingual effect on working memory updating in the conditon of different executive function demands . Bilingual experience could be divided into more bilingual experience and less bilingual experience , so bilinguals were also divided into proficient bilinguals and non-proficient bilinguals . Methods : 36 Uighur-Chinese young adult bilinguals as participants , which involved 18 proficient bilinguals and 18 non-proficient bilinguals . All participants matched at intelligence scores which measured by APM-Set 1.The study included two experimental tasks , namely a simple digit 2-back task and a conflict digit 2-back . The conflict digit 2-back task involved conflict stimuli , and it meant this task involved conflict stimuli to make proactive interference and increase the executive function demands of the task compared to the simple digit 2-back task . Both tasks were designed by E - Prime 1.0 software . The current study was a two-factor mixed experiment design , the types of participants and task difficulties were independent variables , and the types of participants were intersubject variables , while task difficulties which included a simple 2-back task and a conflict 2-back task were variables within subject . The dependent variables were the accuracy and reaction time of targets , non-targets , lures and non-lures . Results : there was significant difference between the simple 2-back task and the conflict 2-back in the accuracy rate of the targets and non-targets , and it meant the conflict 2-back was more difficult than the simple 2-back task ; there was no difference between proficient bilinguals and non-proficient bilinguals in the reaction time and accuracy rate of the simple 2-back task’s targets or non-targets ; there was significant difference between proficient bilinguals and non-proficient bilinguals in the accuracy rate of the conflict 2-back task’s non-targets , lures and non-lures , that is to say , proficient bilinguals were more advantaged than non-proficient bilinguals on the accuracy rate of the conflict digit 2-back task’s non-targets , lures and non-lures . These results suggested that proficient bilinguals had advantages on the conflict working memory updating task but not the simple working memory updating task , which meant the bilingual advantage effect might only show in the working memory updating tasks that involved more executive function demands . Conclusions : (1)Bilingual advantages on working memory updating were not shown in the simple n-back task , because the simple n-back task involved less executive function demands . (2) Bilingual advantages on working memory updating were only shown in the conflict n-back task , because the conflict n-back task involved more executive function demands and might retrieve more cognitive control and conflict monitoring .