As one of the major Chinese dialects, Hakka typically has a tone system with six lexical tones. The traditional 5-level notation of tones in Hakka varies in previous references due to its subjective and relative nature. In order to overcome the limitations of the traditional approach, the command-response model for the process of F0 contour generation is employed to analyze quantitatively the tones in continuous speech of two varieties of Hakka, spoken in Meixian and in Shataukok, respectively. By providing both phonological descriptions to each tone type and quantitative approximations to continuous F0 contours, the model-based approach provides an efficient connection between phonetics and phonology of Hakka tones.