Used by one of the indigenous peoples in the New Territories of Hong Kong, the Hakka dialects cover 54% of the six hundred villages in the area. After the mid nineteenth century, the Basel Missionary Society, a Christian missionary group from Europe with its base in Hong Kong, preached to the Hakka people. They translated and published the Bible in the Hakka dialects using Romanization. They correctly and completely recorded the phonology of the dialects 100 years and more ago. This essay, using the Hakka dialects in Lai Chee Chong荔枝莊as the representative of modern Hakka dialects, makes a diachronic comparison of the dialects, and discovers some obvious changes in their phonology in the pass 100 years and more. For instance, two groups of occlusive fricative and fricative, namely Jing精, Zhuang莊 , Zhier知二 and Zhang章, Zhisan知三, were combined into one. These discoveries are expected to throw light on the diachronic research of the Hakka dialects.