Abstract: New product development (NPD) is a key part of enterprise management and an essential way for enterprises to obtain sustainable competitive advantages. In the context of economic transformation, Chinese enterprises always survive in an environment of high uncertainty and low munificence. Under this circumstance, enterprises gradually realize that it is really necessary to introduce decision-making logic to promote new product advantages (NPA). Effectuation decision-making logic is often adopted by enterprises under conditions of high uncertainty, which emphasizes that experimenting and interacting repeatedly, taking a set of available means and investing resources within the scope of risks that enterprises could take, grasping or creating opportunities by obtaining pre-commitments with stakeholders in advance and making full use of external contingency factors. However, there are some deficiencies in the research of effectuation in NPD. First, previous studies focused on the discussion in an entrepreneurial context and paid less attention to effectuation decision-making logic in the NPD context, such as the discussion on the inner mechanisms between effectuation and NPA. Second, few studies shed light on the mediating mechanism between effectuation and two types of NPA. Based on the summary of relevant theories and existing studies, according to effectuation theory, this paper first analyzes the impact of effectuation on different dimensions of NPA. Then, based on the knowledge-based view, on the one hand, it explores the differentiated effects of two types of external knowledge search on NPA. On the other hand, it discusses the different mediating mechanisms of external knowledge search between effectuation and NPA. In this study, 256 valid samples were obtained by face-to-face interview, e-mail, and postal questionnaire survey methods. All hypotheses were verified by empirical analysis and were supported. The results show that effectuation positively affecting the NPD speed and New product creativity (NPC), and effectuation positively affecting reactive search and prospective search at the same time. Moreover, the positive impact of reactive search on NPD speed is stronger than prospective search, but the positive impact of reactive search on NPC is weaker than prospective search. More specifically, reactive search plays a mediating role between effectuation and NPD speed, and prospective search plays a mediating role between effectuation and NPC. First, this study expands the application contexts of effectuation theory. Our study not only enriches the research on the antecedent variables of NPA, but also provides a new perspective for the following studies on NPD activities. Second, based on the knowledge-based view, this study answers the question of "what kind of intermediary mechanism does the effect logic use to obtain the NPA" by introducing the mediating role of external knowledge search. As a learning strategy, knowledge search promotes the acquisition of NPA by interacting with the external environment, and expands firms’ knowledge resource base with effectuation logic. Thirdly, based on the existing research on the division of knowledge search, this paper explores the differential role of reactive search and prospective search strategies, and improves the related research of knowledge search in the context of NPD.