Abstract: With the advancement of China's Belt and Road Initiative, more and more large and medium-sized construction projects are undertaken. They have the characteristics of large scale and complicated relationship between projects.Single project management theory has been difficult to meet the needs of program management.Due to the large number of participants in large-scale engineering projects, the delays between the various contract projects of the program affect each other, and the mutual responsibilities are difficult to distinguish clearly. It can be seen that the problems that need to be solved in the program schedule management are more prominent.The delay diagnosis of program object control is an important task. The delay of the total construction period of a program can be judged by the total float due to a certain work delay,however,the problem that it is not solved is the delay of a certain work contract and the subsequent contract project.
It is analyzed that the research and application of artificial intelligence algorithm in program schedule management and the principle of artificial intelligence algorithm.According to the multi-project management and program management theory, the sub-network of the program is introduced and the program structure the sub-network is constructed based on the sub-network. The critical path method is used to study in detail the impact of specific work duration delays on the current sub-network and subsequent sub-network durations in the program in a contract item network based on the sub-network contract item. The concepts such as feature process and subsequent feature process are used to diagnose and analyze the delays of the duration of contract items under the sub-network perspective. Finally, the different delay cases are elaborated and applied in combination with the examples, and the delays of different responsible subjects are divided into:in critical lines or in non-critical lines. According to different delay time, the resulting progress impact is divided into:The impact of the project's own schedule or the progress of the subsequent responsible entity project. The results of the example show that the sub-network based on project delay diagnosis can clearly distinguish the sub-network contractor's construction delay liability, and provide basis for the adjustment of project schedule and engineering claims.The data used in the case is representative, and the case results and conclusions obtained from it are universal. The research results in this paper provide a basis for further research on issues related to program management.

Key words: program, sub-network, CPM, delay analysis