This paper proposes that entrepreneurial orientation provides a vision of resource mobilization for various resources provided by alliance portfolio, and alliance process management provides resource coordination to promote the effective utilization of alliance resources. On this basis, it further explores the theoretical boundary of resource diversity affecting the performance. The conclusions are as follows: Firstly, start-ups generate a high level of resource diversity by building alliance portfolio, but the multiple types of resources do not meet their innovation-oriented strategic needs and greatly increase the difficulty of their alliances and resource management, which finally result in the loss of enterprise performance. This is not consistent with the resource-based theory that supports the positive effect of alliance portfolio diversity. After in-depth analysis, it can be found that the transformation of resources into realized performance benefits requires resources to be both “useful” and “usable”, and diversified resources do not meet the above conditions for start-ups, so this research conclusion is a deepening of the resource-based view. Secondly, leverage, as the core process of the resource orchestration process, will have an impact on the mechanism of resource diversity. Specifically, entrepreneurship orientation increases the matching degree of “resources” and “strategy” of start-ups, and resource coordination improves the efficiency of resource allocation and utilization, which weakens the negative effect of resource diversity on entrepreneurship performance. The implications lie in that: Firstly, start-ups mainly adopt innovative strategies. Therefore, it is necessary to effectively identify resources according to the development status and strategy so that they can be useful. Secondly, if an enterprise can maximize the effectiveness of resource mobilization and coordination, resources will be easier to play the supporting role for corporate strategy, thereby maximizing the value of resources. Thirdly, start-ups can amplify the strategic value by improving the entrepreneurial orientation and the institutionalization of alliance resource process management. The contributions are that: Based on the uniqueness of start-ups, this paper reveals the negative effects of resource diversity, and responds to the paradox of alliance portfolio diversity. On this basis, resource orchestration theory is applied to explore how start-ups manage resources actions to realize the value of resources and to enhance performance, which expands people’s understanding of resource orchestration. At the same time, from the perspective of resource combination constructed by the enterprise, entrepreneurship orientation is regarded as the operational definition of resource mobilization, which enriches the theoretical connotation of entrepreneurial orientation.