Phonetization is an important component in Chinese TTS system. However the polyphonic characters make this problem more complex. This paper reports the study on the relation between the Chinese characters and their pronunciation, proposes the solution to the disambiguation of polyphonic characters, dictionary-based method, and rules-based method. In the rule-based method, we used the statistic decision list method. The phonetization plan is proved effective in the experiment. Most of the improvements on the accuracy of polyphone phonetization are beyond 10%.