In this paper an overall approach of technology acquisition by using a priority setting method is proposed. In the management of technology literature, different methods of Technology Acquisition were developed. We categorized them into three levels: mode, mechanism and operational models. In this paper we developed an algorithm for choosing the best mode of technology acquisition in the specific technology. The algorithm is combination of critical technologies method and some criteria such as cost of technology acquisition mode. Concurrently priorities of technologies will be set. Finally we applied this approach to membrane technology in Iranian petrochemical industry.