Abstract. It is very important for investors to understand the critical factors affecting the value of firms before making investments. In knowledge-based economy, the method for creating firm value transfers from traditional physical assets to intangible knowledge. As intangible assets value is an important part of firm value, valuation of intangible assets becomes a widespread topic of interest in the future of economy. This paper applies association rules, one data mining technique, to discover critical factors affecting firm value in Taiwan and to provide a more flexible model than the traditional regression method. Based on collecting related factors found in literature, the results indicate that R&D intensity, family, participation in management, pyramids, profitability, and dividend are the six important factors, in which some are consistent with significant important variables in prior literature, but most of them are unique for Taiwan, one emerging economy.