Promoting the deep integration of advanced manufacturing and modern service industries （"integration of two industries"） is a crucial pathway to enhance the core competitiveness of the manufacturing sector，accelerate the formation of new quality productive forces，and achieve Chinese-style modernization. Data openness provides a new opportunity for this endeavor. Based on the data from Chinese cities spanning 2006 to 2020，this paper constructed a quasi-natural experiment using the launch of local government public data platforms，and employed the multi-period difference-in-differences models and mediation effect models to empirically test the impact and mechanisms of data openness on the "integration of two industries". The study found that： （1） Data openness significantly promotes the "integration of two industries"；（2） The heterogeneity analysis indicated that the promoting effect of data openness on the "integration of two industries" is more pronounced in cities located southeast of the Hu Huanyong Line，cities with lower administrative levels，and cities with favorable business environments；and （3） The mechanism analysis revealed that data openness helps reduce transaction costs，enhance intellectual property protection，and accelerate the digital transformation of both manufacturing and service industries，thereby empowering the "integration of two industries". This study will provide theoretical and empirical support for how data openness can empower the "integration of two industries" and offer policy recommendations for promoting the integration of the two industries，creating new manufacturing，new services，and new business models，and advancing Chinese-style modernization.