This paper aims to investigate whether bi-dialects have cognitive advantages over mono-dialects in cognitive executive control tasks, for there remains controversial about the intrinsic cause of the bilingual advantages. One explanation is that this bilingual advantage in executive control derives from the collective control of many language subcomponents, such as grammar, semantics, orthography, phonetics, and lemma. Others argued that bilingual advantages mainly stem from modality-specific articulatory constraints that forces language selection. Eighty middle school students aged from 12-13 years old participated in the present experiment. Among them, 40 students from Tai-zhou, Jiangsu Province could speak both the standard Chinese Mandarin (Pu Tong hua) and the Tai-zhou dialect (i.e., the bi-dialect group), while the other 40 students were from Beijing who could only speak the standard Chinese Mandarin (Pu Tong hua) (i.e., the mono-dialect group). All students had normal or corrected-to-normal vision and had no serious mental diseases or neurological disorders. After excluding the data with low accuracy, 35 bi-dialect and 37 mono-dialect participants were included in the final analysis. Language history questionnaire indicated that there were significant differences in the standard Chinese Mandarin proficiency between the two groups with the mono-dialects being more proficient. As to the bi-dialect group, the proficiency of Tai-zhou dialect was superior compared to the standard Chinese Mandarin. What’s more, there were also significant differences in the use of the two dialects. Moreover, the two participant groups were matched on factors that may have impact on executive functions, including IQ (measured by Raven Standard Progressive Matrices, RSPM) (Zhang & Wang, 1985) and demographic variables. In the experiment, participants were asked to perform two tasks in a quiet room: cue-switching and phonetic stroop. At the same time, their reaction time and accuracy of response were recorded. The whole experiment took about 50 minutes. Participants got a small gift at the end of the experiment. Results showed that bi-dialectal speakers showed no advantages in general executive control tasks, but they do better than mono-dialects in phonetic stroop task. In the cue-switching task, a task mainly exploring the abilities to shift between mental sets, no significant differences between participant groups were found, but significant trial effects were observed, such that the response was faster and accuracy higher for non-switch tasks than for switch tasks. In the phonetic stroop task, bi-dialects were found to have some cognitive advantages, which was revealed by RTs but not by error rates. On the other hand, significant differences were found in trials (match\irrelevant\conflict) in both RTs and error rates. In conclusion, the present study was the first one to compare the performance of mono-dialects and bi-dialects in switch task and phonetic stroop task. The results from switch task showed no significant differences between the two groups, but the results from phonetic stroop task indicated that bi-dialects have advantages in tasks involving phonology processing to some extent, suggesting that phonetic competition may lead to bilingual advantage in executive control function. Thus, we concluded that bilingual advantages may be a joint result, in which grammar, semantic, phonology, and other language subsystems worked collectively.