Industrial equipment products had been developed for a small and compact design. Cooling system is also developed to mini heat exchanger with microchannel as main component. The main study is to find the characteristic of flow pattern and heat transfer effect in microchannel. The experiment has been done with visual apparatus that placed after outlet of test section with inner diameter 0.5 mm. The working fluids used is a natural refrigerant (propane) that operated on a vary parameter of experiment condition i.e. saturation temperature, mass flux and heat flux. Mapping of flow pattern used Wang's Map. The result experiment reported intermittent flow pattern occurred along operated experiment. Heat transfer showed increasing value on initial occurred two phase. The observation to visual data has reported as additional of experiment analysis.