## 1 Introduction  
Nowadays, improving scientific and technological innovation ability has become the theme of the times. Enhancing regional science and technology (S&T) innovation ability is the basis for promoting the regional economic level and constructing an innovative country. Regional S&T innovation is a part of sustainable development, and regional S&T innovation itself should have a focus on sustainable development. Progress in regional S&T innovation is the driving force behind sustainable development, which is a subtopic of sustainability. In recent years, the pressure of upgrading China's economic structure has continued to increase. Under the pressure, the regions have more urgent demand for S&T public services such as common technology R&D, technology transfer and promotion, popularization of science and so on. China has always attached great importance to the construction of public S&T service systems. In 2012, the State Council issued the \"Opinions on Deepening the Reform of Science and Technology System and Accelerating the Construction of National Innovation System\", which regards improving ability of S&T public services as an important measure for the reform of S&T management systems. In 2019, the Ministry of Science and Technology issued the \"Several Policies and Measures on Supporting Scientific and Technological SMEs to Accelerate Innovation and Development in the New Era\", which clearly proposed to improve China's S&T innovation ability by increasing the supply of S&T public services. However, the market-oriented supply of S&T public services is insufficient, and the contradiction between supply and demand in S&T public services hinders the improvement of regional innovation ability. Therefore, as an important S&T policy, Government Purchasing Science and Technology Public Service (GPSTPS) has attracted much attention because it helps to provide professional and personalized S&T services, improve the supply efficiency of S&T public services and accelerate the transfer of government functions [1]. Enhancing the quality of S&T public services and implementing the policy of GPSTPS are important measures to promote regional S&T innovation ability. China began to implement Government Purchasing Public Service (GPPS) in the 1990s. As a means of public governance, GPPS policy has become an important way to promote the construction of service-oriented government. In the early stage of policy implementation, purchase objects mainly focused on basic public services such as medical and healthcare, elderly-care services and community services. In recent years, with the urgent demand for S&T public services and the state's strong call for GPPS policy, GPSTPS policy has begun to be widely implemented in various regions. S&T public services refer to the services provided by governments dominantly to satisfy the needs of innovation subjects, promoting the transformation and industrialization of technological achievements. Over the years, central and local governments have actively issued policies on GPSTPS, so as to increase the supply of S&T services and enhance the regional S&T innovation ability. With the help of PKULAW, which is a professional legal inquiry software in China, 412 laws and policies are retrieved through taking \"Government Purchasing Science & Technology Public Service\" as keywords during 2008-2017. For example, the \"Several Opinions on Accelerating the Implementation of Innovation-Driven Development Strategy\" issued by the State Council in 2015 pointed out that the procurement of science and technology services and products is supposed to be increased and the implementation of GPPS on S&T services is encouraged, so as to improve the application of innovative products. GPSTPS also faces some obstacles during the practices. Localities are supposed to explore the optimal purchase mode which is suitable for the characteristics of S&T public services, and the purchase boundary of GPSTPS should be determined.