## 1 Introduction  
As an important policy tool, developed countries spend over 10% of gross domestic product on their public procurement [1] and it is widely recognized that laws and regulations can be effective driving force for green public procurement (GPP) practices adoption and Chinese government has enacted a series of GPP policies [2]. In 1984, the US \"Government Procurement Law\" clearly regulated that the government should procure environmentally sound products and services, which meant that GPP has legal support for the first time. The \"Agenda 21 at the United Nations Conference on Environment and Development\" indicated that unsustainable production and consumption are the main reasons causing global environmental problems, and the government should control and eliminate these behaviors. Furthermore, GPP is an effective means of sustainable consumption. In 2004, The EU issued a directive on government procurement, in which environmental requirementsneed to be considered while procuring and signing a contract. In China, GPP has been attached great importance with the government [3]. In 2006, the \"Implementation Opinions on Environmental Labeling Products in Government Procurement\" and \"Environmental Labeling Products Government Purchasing List\" were issued to ensure that the products were green and GPP practices were carried out successfully [1]. The latest relevant policy, for instance, in 2015, \"opinions on accelerating the ecological civilization construction\" made a proposal to promote energy-conserving and environment-protecting products to boost consumer demands, and established energy efficiency and environmental protection logo certification system to accord with national situations and act on international convention. Then, \"guidance on promoting the positive leading role of new consumption to speed up the formation of new supply and new impetus\" in 2015 and \"guiding opinions on promoting green consumption\" in 2016 put forward to lead production mode change by health savings green consumption patterns, to improve the system of GPP, and to expand the scope and scale. \"The Thirteen Five-Year Plan\" identified five development concepts including green ideas, which indicated that the government should play a guiding role in the green consumption and green procurement. GPP has received international attention because of the influence of its social and economic aspects [4]. Currently, the transformation of green production mode in China has reached a critical stage, and as an important part of demand side, GPP could force supply side to reform, which has been a hot topic in the related document about the development of an ecological civilization. On the other hand, as the government procurement scale grows and products in the list of government procurement keep on increasing, the government green purchase is developing rapidly. However, GPP practice is still too weak to meet the needs of development. Green procurement could achieve sustainable development goals through the purchasing and supply process, and it should consider at least four themes: moving from an environmental focus to social and economic dimensions; sustainability and innovation; ethical supply; and measurement issues. Above all, measurement issues, especially quantitative evaluation, are urgently in need of research [5]. However, in past studies, product evaluation often centered on a single product; consequently, it is also important to establish a screening system in which most kinds of products can be evaluated. That means we need to found a new general way to weigh the environmental performance of products beyond the scope of \"government procurement list\". This paper will provide a green product screening system to measure the green degree of different products in \"list\" by quantitative evaluation method. We established an indicator system, including basic indicators, common indicators, and oriented indicators, to rate different product by scores.