Green roof application on real commercial building in Australia is very limited and mostly concentrated in major cities mainly for visual purposes. There is not enough research has been conducted to boost up the benefits of green roof system in hot and humid weather in Australia. Before implementing the roof top greenery systems, it is really important to investigate its thermal performance which can be obtained by experimental data collection and analysis during different seasons so that seasonal variation can also be observed. An experimental study of an extensive green roof is presented in this paper. The paper investigates the thermal performance of a green roof and without green roof over a 6 meter long steel structured standard shipping container which locates in Central Queensland University, Rockhampton campus, Australia. A temperature difference of up to 4 oC was observed in a typical summer (February) day.