Previous studies on the diachronic and synchronic evolution of Chinese comparative sentences show that comparative constructions have developed from "comparative result + comparative object" type to "comparative object + comparative result" type. We further explore the diachronic change of comparative constructions in Hakka dialects. The corpora adopted in the paper include the Basel missionaries at the end of the nineteenth century, and Basic Hakka Vocabulary for Hakka Language Proficiency Examination-Intermediate, Intermediate and Advanced Materials (2014). The analysis shows that the dominant comparative constructions in Hakka dialects in Taiwan are those with double markers. It is observed that the Hakka data also follows the tendency, i.e., from "comparative result + comparative object" type to "comparative object + comparative result" type, but in addition, the comparative sentence patterns with double markers become dominant in modern Hakka dialects. Such phenomenon is found in Dream of Red Mansions, written in Qing dynasty, so the comparative constructions with double marker are not exclusive in Hakka dialects.