Abstract: Abstract: China is experiencing a transition to the new normal economy, new product development (NPD) has become an important strategic tool for enterprises to maintain the leading position in the market. However, the scarcity of innovation resources and the uncertainty of institutional environment often limit the NPD activities of enterprises, which makes it common for enterprises to obtain complementary resources and reduce risks through cooperation. Among all kinds of cooperative relations, the cooperation with direct competitors has gradually attracted the attention of scholars, namely horizontal coopetition. Horizontal coopetition can not only create joint value, it is worth mentioning that enterprises themselves can also create additional profits through the resources and new technologies obtained in horizontal coopetition. However, the inherent contradictory logic of coopetition is also the source of potential risks such as opportunistic behavior, knowledge spillover and bargaining. Therefore, how to better play the value of horizontal coopetition to improve NPD advantage has become a key problem faced by enterprises. Based on the sample data of 229 enterprises, the relationship between horizontal coopetition and NPD advantage is tested, as well as the moderating effect of the two coopetition modes. The results show that horizontal coopetition has a positive effect on new product innovativeness (NPI) and new product development speed (NPDS). Equity coopetition strengthens the positive effect of horizontal coopetition on NPI but weakens the positive effect on NPDS, while contractual coopetition strengthens the positive effect of horizontal coopetition on NPDS but weakens the positive effect on NPI. This study has important theoretical significance in three aspects. First, this study focuses on the specific type of horizontal coopetition, and refines the related research on the coopetition theory. Specifically, most empirical studies generalize coopetition, obscuring the particularities of different types of coopetition and their specific effects. This paper explores horizontal coopetition, a specific type of coopetition, not only responds to the call of scholars to refine the study of coopetition type, and broadens the research of horizontal coopetition in the field of new product development research, makes up for the shortage of research on the value of horizontal coopetition in improving NPI and NPDS, also supplements the important contextual factors that affect the value of horizontal coopetition. Second, this study deepens the research on the antecedent variables of NPD advantages from the coopetition perspective. Existing studies have ignored the influence of horizontal coopetition on NPI and NPDS. This paper explores the mechanism of horizontal coopetition on NPI and NPDS under the background of NPD, and provides a new perspective for subsequent research on new product development based on the coopetition theory. In other words, this paper is a useful supplement to the research on the antecedent factors of NPI and NPDS. Thirdly, this study integrates the coopetition theory and the transaction cost theory, and fully considers the importance of coopetition modes to the NPD advantage and the possible transaction cost differences of different coopetition modes when enterprises develop new products through horizontal coopetition. The cross-fusion of the two theories is conducive to further reveal the moderating effect of coopetition modes on the relationship between horizontal coopetition and NPD advantage.