Abstract: Optimal design of gathering system is a kind of large and complex hybrid optimization. Some problems are of NP problems. Depending on network structure, optimization variables, objective function and variable types, a number of optimization problems are generated. With the emerging of various optimization designs, it is necessary to give a systematic classification of network design optimization. Therefore, considering the structural solvability, this paper presents the issues in gas gathering design at home and abroad, and proposes a five-parameter classification method. Difference and relevance of the problems are clarified. With this method, the domestic and abroad researches thereof are sorted out. The results show that optimal design of gathering system is heading towards "multiple structure types, multi-parameter fusion, higher space and efficient algorithm", and it can serve as references of system structure for researchers.