Resource and material costs are significant proportion of total construction cost in civil and construction engineering. The purchase of these resources and materials need to coordinate with different suppliers. The selection of suppliers plays an important role in construction process management. This research will focus on delivery and try to define an index of performance of formwork process to evaluate the suppliers. Moreover, the index also provides a convenient and effective way to evaluate various suppliers' performance of formwork process at the same time. This paper uses Boyle's rate of tallied tolerance of index of process capability and Taguchi Loss Function as a non-dimensional equation to define an index of performance of formwork process that has the rate of as scheduled delivery as basis. In addition, this paper also refers to Vännman's method to develop an analysis chart of performance of multi-formwork process to compare the performance of every supplier. When implementing the analysis method developed by this paper into practical examples, it is very convenient and accurate to express the relationship between the index of performance of formwork process and rate of as scheduled delivery.