Pun is a special rhetoric device. It is very hard to find the equivalence in the target language. However, with the help of Relevance Translation Theory, we may achieve valid reconstruction of pun in translation. The issue of valid reconstruction of pun in translation by quoting the examples of phonological pun and semantic pun from The Story of the Stone by David Hawkes is analyzed. In order to achieve valid reconstruction of pun in translation, translators should take the target audience’s cognitive environment, expectation of relevance and processing effort into consideration. On the basis of that, translator can adopt proper way to guide the audience to infer the implicit meaning of the pun in consistency with the principle of relevance. It proves the power of Relevance Translation Theory in pun translation and provide roference for the other rhetoric devices.