The strategies /of two duopoly firms, which are characterized by different quality, network externality coefficient, compatibility, switch costs, were studied after Hotelling model with longitudinal product differentiation and quadratic transport costs was introduced. For two firms, their locations and, competitive in price were chose simultaneously. Equilibrium market strategies of duopoly firms with Horizontal and longitudinal product differentiation are obtained, so, Hotelling model is extended. Under the assumption that duopoly firms would choose their maximal horizontal product differentiation, The influence of differentiation products quality, network externality coefficient, compatibility coefficient and switch costs on the duopoly' competition equilibrium was analyzed.