Abstract: At present, many countries and regions in the world, such as China, are advancing the integrated development of the internet, big data, artificial intelligence, manufacturing, agriculture, and service industries, and simultaneously promoting the development of manufacturing, agriculture, service industries in the direction of digitalization, networking and intelligence. However, informatization construction is the foundation for enterprises to realize the development of industrial integration and the development of digitalization, networking and intelligence. In the process of informatization construction, software developers such as ERP vendors and APP venders need to cooperate to provide software products (such as ERP systems, CRM systems, etc.) and related services (such as consulting, demand analysis, installation and testing, maintenance, upgrades, etc.) to client enterprises. The present research investigated the supply chain decisions and contract design strategies under the constraint of exogenous factors in the tripartite interaction process, such as a customer enterprise's quality perception, delivery sensitivity and demand change, by establishing profit-based decision models of ERP manufacturers and APP developers from the perspective of game theory, and designing the cooperation contract based on fixed compensation, service commitment and time penalty. Results of the present research show that: Firstly, according to the requirements of customer enterprises on software quality, delivery time and the possible changes in the software development process, the software developer can choose four delivery strategies, including on-time delivery with demand quality, on-time delivery with high quality, early delivery with demand quality and early delivery with high quality. Secondly, the default risk borne by the ERP manufacturer is largely affected by the cost of software repair or maintenance. For example, when the repair or maintenance cost is less than a certain threshold, the risk increases as the cost goes up, whereas when the cost is greater than this threshold, the risk correlates negatively with the cost. Thirdly, under certain conditions, the customer's demands and requirements changes will not affect the software developer's product delivery decision. However, the emergency rush cost has a great impact on APP manufacturers' efforts and time delivery decisions in these conditions. When the emergency rush cost falls into three different ranges, the APP manufacturer has three contract design strategies accordingly, namely increased effort investment with extended delivery time, increased effort investment with shortened delivery time, and reduced effort investment with shortened delivery time. Lastly, in addition to cooperation contracts based on fixed compensation, service commitment and time penalty, the ERP manufacturer can also provide cooperation contracts based on fixed compensation, service commitment and delivery time, and the cooperation performance generated by the two contracts is equal.

Key words: product service supply chain; demand change; contract design; mobile application