This research aims to propose a symbiosis model for new product development based on the open innovation concept. Particularly, a dynamical model of Lotka-Volterra approach is used to analyze the cooperative R&D relationship between the innovation intermediaries and R&D firms, the patent seekers, to share their patent portfolio or resources in the open innovation process. The study will develop a symbiosis model to assume the growth rate, growth limitation, and positive interaction effect of both R&D firms and innovation intermediaries, for best discussing the market situation in four different empirical cases. Simple numerical examples will also be adopted to demonstrate the utility of market research in this model and propose the strategic suggestion of different mutualism relationship between a R&D firm and an innovation intermediary.