Once nonprice strategies serve as the main tool for competition and the price rigidity exists, the quantity data such as market shares instead of price data may be employed for the analysis for product substitutability. Following the technique developed by Rothschild, Swann and Taghavi (1991), this study revised their model by introducing the hedonic price instead based on the correlations in the market shares of different brands for Taiwan cigarette industry. Results of this study indicate that: there exists signification brand substitutability within the group of domestic cigarettes, this is also true for the group of imported cigarettes. Furthermore, a weaker substitution is observed between some domestic brands and imported brands.