Tone merging and tonal confusion have been an interesting issue for a long time. This paper tries to investigate whether there is the phenomenon of merging tone in Hailu Hakka production. We focus on sandhi related tone pairs and level tone pairs. The results show that tone 24 and tone 33 is undergoing a sound change of merging in the younger speakers. It is proposed that both allophonic rules and acoustic similarity contribute to the merging tone 24 and 33. Index Terms: tone, merging, Hakka, sandhi, production, allophonic rule, acoustic similarity