Do you mean Yuyao in Ningbo City, Zhejiang Province? If yes, there is no direct train from HK to Yuyao. However, you could take one train from Kowloon to Guangzhou first, and then take K210/K211 to Yuyao directly. Or, you could take K326/K327 to Wenzhou from Guangzhou first and then take one coach or train to Yuyao.