The Qianjiang(潛江) city is located not only on the boundary of the Southwestern mandarin and the Gan dialect, but also on the boundary of three different sub-cluster regions of the Southwestern mandarin. Therefore, it is difficult to classify the Qianjiang dialect into any region. As a result, the phonological features of the Qianjiang dialect have not yet been systematically studied so far. In order to provide a thorough understanding of the Qianjiang dialect, this thesis focuses on investigating phonological characteristics of the Qianjiang dialect and in particular the aspiration of the Middle Chinese (MC) voice obstruent. As many ancient phonological characteristics are still preserved in today’s Qianjiang dialect, the study also helps us better understand the immigration history of Qianjiang as well as its impact on the Qianjiang dialect. First of all, a summary of phonological characteristics of the Qianjiang dialect is carried out. A set of distinctive phonological characteristics are listed and analyzed with respect to both initials and finals of the Qianjiang dialect. For example, the MC zhongchun(重唇) sounds, the Jiantuanyin(尖團音) , the MC value of the jia (假) rhyme group, the guo (果) rhyme group, and the ji (祭) and qi (齊) rhyme which belong to the historical stratum of Middle Chinese are preserved in the Qianjiang dialect. Those phonological characteristics of the Qianjiang dialect belong to the stratum of the historical stratum of the Southwestern Mandarin are also described in this thesis, such as the confusion of the MC initials ni (泥) and lai (來), the MC zhi (知) group, zhuang (莊) group and zhang (章) group in the Qianjiang dialect. The development from [u] to [«u] of the mo (模) Rhyme in the yu (遇) rhyme group, and the entering tone, wu (屋), wo (沃), zhu (燭) rhyme in the tong (通) rhyme group in the Qianjiang dialect. As a unique characteristic of the Qianjiang dialect, the aspiration of the MC voiced obstruent is thoroughly analyzed in historical and geographical contexts. From the analysis, it can be drawn that the Qianjiang dialect has been impacted by immigrants from northwestern areas during Tang dynasty as well as immigrants from Jiangxi(江西) province during the Ming and Qing dynasty. In addition, the theory of hypercorrection has been established to explain aspirated sound of MC Quanqing (全清 voiceless unaspirated stop and affricates) initials in the Qianjiang dialect. From the investigation of the phonological characteristics of the Qianjiang dialect, this thesis considers the Qianjiang dialect as a dialect transition region between two sub-regions of Southwestern Mandarin represented by the Chengyu(成渝) region and the Wutian(武天) region. The Qianjiang dialect itself has inherited phonological features from immigrants of other areas and do stand out as an important language resource to mirror the profound historical shifts in Chinese history.