The objective of this thesis is aimed to provide the project costing for project master budgeting in fabrication and installation machine transportation including belt conveyor, bracket conveyor, stock silo, and vibrating screen. The project auction for machine transportation that present to the method of project management. After that management cost is are allocated to the machine and then allocated to fabrication and installation machine transportation. Finally the computer program developed in this work is a tool for supporting cost calculation and reporting for decision making in competitive in the project auction for machine transportation. The old method of estimating project cost for the auction that estimate all expense in the project was share by weight of machine in the project. For project costing system improvement, the Critical Path Method (CPM) for project planning and estimating was used and applied that by direct labors for allocating the management cost to fabrication and installation machine transportation. This work has made the costing each machine fabrication and installation that compare with the new add costing system, we found the new give the machine cost 2,426,596 baht of fabrication and the record 2,708,784 baht, difference is about 12 % and the record of installation machine cost is 4,127,669 baht whereas the new method is 3,845,984 baht, difference is about 7% Above it made the significant that could affect the decision making and price for auction. The result of this work is accuracy and provides for project costing control efficiently.