## 1 Introduction  
The modern world is facing multiple rapid changes and problems resulting from them. Radical innovation (RI) is an effective way to cope with changes and solve problems with revolutionary technology [1]. Radical innovation provides entirely new function, unprecedented performance benefits, substantial cost reductions, and new marketing opportunities for the development and commercialization of products/services offered [2, 3]. For examples, 5G technologies accelerate the transformation and upgrading of traditional manufacturing [4] and health care industries [5]. Artificial intelligence brings new opportunities for autonomous driving and smart medical care [6, 7]. Therefore, many firms are willing to engage in radical innovation activities, hoping to establish technological advantages and gain more market share. However, only a small number of innovation projects have truly reached the level of radical innovation, and the majority of innovations are still incremental innovations [8, 9]. In new product development, design concepts decide as much as about 80% of the work and cost for the whole development [10]. A successful radical innovation project begins with a reasonable radical concept or idea that provides a unique solution for innovation and has enormous business value. Further research shows that the radicalness of RI usually depends on uniqueness of new technologies which comes from the result of cross-domain knowledge application to solve a difficult problem [11, 12, 13]. Cross-domain knowledge refers to knowledge that comes from domains other than the domain in which the problem needs to be solved [14, 15]. Research in radical innovation management has demonstrated that cross-domain knowledge has an important inspiring effect on the RCG [16, 17]. [PERSON] [18] and [PERSON] [19] realize that open innovation, e.g., alliance network and partnerships,enables firms to acquire more cross-domain knowledge from the outside and stimulates the RCG. Further research suggests that the better the absorptive capacity, the more favorable it is for firms to acquire cross-domain knowledge for RCG [20; 21; 22]. Researchers above mainly focus on how to improve firm's access to external knowledge to generate radical ideas. However, the development and application of cross-domain knowledge for RCG is a complex multi-standard decision-making process [23; 24]. Not all knowledge from outside can help engineers to generate radical ideas and concepts. How do we accurately search the cross-domain knowledge suitable for the development of radical ideas? How do we develop radical concept based on the cross-domain knowledge? Therefore, approaches to grasp key techniques precisely to search, screen and utilize the cross-domain knowledge for RCG have to be further studied [25]. A systematic process management method of cross-domain knowledge for RCG is still lacking. The aim of this paper is to establish a process management method of cross-domain knowledge development for RCG. Building on the strategy literature and research of related theories, the predictive function of the law of the technological evolution and the advantage of minimum complement distance measurement are suggested to connect with radical innovations to address the above problem. Radical technology opportunities are identified based on the analysis of the dynamic relationship between customer needs and technical performance. Laws and lines of technological system evolution are used to determine the search direction of cross-domain knowledge in a qualitative perspective and select cross-domain knowledge in the minimum complementary distance in a quantitative perspective. Finally, radical ideas and concepts are established with cross-domain knowledge as inspirations. The precise process reduces uncertainty in cross-domain knowledge search and increases the efficiency and success of RCG. Remaining parts of the paper are organized as follows.