The Ground Based Augmentation System (GBAS) ground facility prototype, called the Integrity Monitor Test-bed (IMT), is developed to facilitate the GBAS implementation and operation in Taiwan Flight Information Region (FIR). The IMT evaluation module includes five IMT reference stations and one IMT master station. The objective of this paper is to investigate the effects of different site distributions of the IMT reference stations on the IMT performance. The developed IMT evaluation module is deployed at Taiwan Kaohsiung International Airport (ICAO Code: RCKH) to conduct several experiments with different site distributions of the IMT reference stations. Accordingly, this paper begins with the software and hardware architectures of this proposed IMT evaluation module, and then the deployment of this IMT evaluation module at RCKH is explained. The experiment results of different site distributions of the IMT reference stations are intensively evaluated in this paper..