Considering the two characteristics of activity splitting and resource window in the process of aircraft assembly，the model and algorithm of Resource Investment Problem on aircraft mobile production line were studied. Aiming at the situation that some activities have known splitting mode and splitting punishment，an improved genetic algorithm for solving this problem was designed. The traditional real value crossover operation was optimized，and a crossover method based on chromosome fitness value was proposed. Sensitivity analysis was carried out on the range of values of the relevant parameters. A mutation mechanism based on the probability of selection of activity start time was also proposed. For a scheduling scheme that satisfies the optimization conditions，combined with the position of the resource window，after judging whether the splitting activities can be re-scheduled and executed by selecting a new splitting mode and summarizing the different situations，the target resources were further reduced by local operations. The numerical experiments show that，compared with the results of solving the problem of non-split activities with resource window and the basic problem，the average value of the target for the 10，16，30，60，90 activities is 4.3%. For the comparison between the results of solving this problem and the non-split problem，the average optimization rate is 3.5%，which proves the effectiveness of the algorithm. At the same time，it is proved that the activity splitting is included in the Resource Investment Problem considering the resource window，which can improve the flexibility of problem solving and obtain better scheduling results.