Juntong, N. Chanwattana, T. Kittimanapun, K. Pulampong, T. JACoW Publishing Geneva, Switzerland The future synchrotron light facility in Thailand is in designing process, which has a goal to complete a detailed design report in 2018. The new light source will be a ring-based light source with the circumference of approximately 300m and an electron energy of 3GeV. The maximum beam current is 300mA with a beam emittance below 1.0 nm·rad. The accelerator is based on a full energy linac, which will utilize a S-band frequency structures. The RF system of the storage ring is based on 500MHz frequency. The EU-HOM damped cavity and the new SPring-8 design TM020 cavity is the choice of the storage ring cavity. The RF power transmitter can either be a high-power klystron (1 MW klystron) feed all RF cavities or a combination of low power IOTs or solid-state amplifiers feed each cavity. The high gradient S-band structure is considered as the main accelerating structure for linac. The RF power system for linac will base on klystron and a modular modulator. This paper presents details of RF systems options for this new light source project.