Treatment of fresh fruits, meat, and food with ionizing radiation has been frequently chosen to destroy harmful pathogenic microorganisms and oriental fruit flies. Electron beam linear accelerator (Linac) is commonly used as the source of irradiation to produce photons and electrons in megavolt energy. A 6 MeV Linac designed for medical therapy has been developed for fresh fruit sterilization at Synchrotron Light Research Institute (SLRI). Some physical design and beam dynamic results of the electron gun and 6 MeV Linac will be presented in this paper. Testing of each subsystem and installation of the 6 MeV Linac with major auxiliary systems will be described in this paper. It is the first system designed, fabricates, and tested in-house for the fruit sterilization application at SLRI. Measurement results of the Linac properties are presented as a resonant frequency and coupling coefficient at low power called a cold test. The Linac system with all sub-systems and the auxiliary systems will be installed and tested before x-rays production. During commissioning some electron beam parameters out of the electron gun and the Linac exit will be measured.