In the present study, some mud volcanoes in Pingtung(Wan-Dan mud volcano) and Kaohsiung(Niau-sung mud volcano) areas were selected. The selected mud volcanoes are located above the mud diaper system in southern Taiwan. Three different sampling techniques were used to collect samples in and around the said mud volcanoes. The results show that river water samples from various locations fall on the meteoric line. Mud samples are found to be heavier in oxygen isotope while hydrogen isotope remains the same. Soil gas samples were also collected at a depth of 1 meter and dissolved gases from the mud volcanic site(or nearby) were collected for GC(Gas Chromatography) analyses. Soil gas samples and dissolved gas from mud pool and groundwater were analyzed for radon concentration using RAD7(Solid-state nuclear track detector) bi-weekly. Long term investigation will be needed to understand the relationship of mud volcanoes eruption cycle with gas composition variations. It will also help to understand their relationship with tectonic activities in the region.