In the modern world, construction projects are recognized as one of the main components of economic and social development. The efficiency of machinery plays a key role in these projects. However, the lack of proper maintenance of these equipments can lead to them being out of service and increasing operational costs. Therefore, the necessity of investigating and analyzing the role of maintenance in cost optimization is a vital issue. The effective maintenance and repair of machinery is considered one of the main pillars of construction project management. This research examines the direct and indirect effects of machinery maintenance in Jihad Nasr Kerman Company as a case study. Therefore, by implementing the optimization process with the general algebraic modeling system in the GAMS software, data analysis has been done. The results of this analysis showed that neglecting the optimal maintenance can lead to an increase in breakdowns, delays in project time and In the end, the costs will increase. On the other hand, investing in preventive maintenance programs can reduce unexpected downtime, increase equipment useful life, and improve overall project efficiency. Also, by applying asset management techniques and cost-benefit analysis, this study provides suggestions for optimizing maintenance programs. In conclusion, this paper emphasizes the importance of maintenance management as a key strategy to reduce costs and increase productivity in construction projects.