This study re-investigates the merger of *-iun/iut and *-un/ut in 46 Yuè Chinese varieties, which lacks explanatory treatment, from the variant derivative patterns of *-iun/iut > [yn]/[yt] and *-un/ut > [yn]/[yt]. The historical-comparative method was employed as the frame to analyze spatial (geographic) variation obtained from QGIS. The data showed that the merger of the reflexes of *-iun/iut and *-un/ut does not prevail in the majority of Yuè varieties, while mergers of *-iun/iut with *-in/it and *-iun/iut with *-on/ot or *-ion/iot are dominant. The spatial patterns of *-iun/iut and *-un/ut suggest different diffusion patterns and background factors.