With the approval of the law for supporting knowledge-based firms in 2010, a new wave in Iran's science, technology and innovation system began with a focus on the knowledge based economy and innovation-based. Currently, there are more than 4,000 knowledge-based firms in Iran that nearly 5% of them are active in biotechnology. The aim of the present study is to design an empirical model of the relationship between financial and tax incentives of this law on some of the performance indicators of biotechnology knowledge-based firms. For this purpose, after analyzing the content of related documents and designing the study model, for evaluating the direct and interacting effects between policy tools, identifying the important empirical factors and their level, "2³ factorial design" was used. Study target community includes 113 manufacturing knowledge-based firms in the field of biotechnology. The findings of this study on input additionality indicators show the positive effect of the threefold interaction of factors on the R&D expenditure and the positive effects of commercialization financing and technology financing and their interactions on R&D employee. In the present study, there was no relationship between the effectiveness of policy tools on output additionality indicators.