The research of the influence of cooling load on the measurement of R-134a refrigerant evaporation heat transfer coefficient in horizontal fine channel is very important to do because by knowing the cooling load contained in a room, such as the number of occupants, the number of electronic goods, as well as the time of day and night Affect the variation of cooling load on the cooling machine where the heat absorbed by the evaporator may change. The heat changes absorbed by this evaporator are thought to be influenced by changes in the evaporative heat transfer coefficient so that it needs to be investigated. The method used in this study is an experimental method by varying the water mass flow rate (cooling load) to the evaporator and also set the frequency of the inverter to adjust the variation of refrigerant flow rate. Where the evaporator is placed in a tub with a size of 25 cm x 15 cm x 20 cm which will be filled with water and the debit is measured using a water rotameter. The test is done by using a simple vapor compression test modified by adding heater, test section, and orifice. Where at the point that has been determined put pressure gauge and thermocouple to take data pressure and temperature. The refrigerant used is R-134a. The results of this study indicate that the value of evaporative heat transfer coefficient increases with the increase of cooling load capacity given into the evaporator, with the added cooling load per one variation of the mass flow rate hence the highest hevap evaporative coefficient value is 4273, 5310 W / m2K at a frequency variation of 24 Hz inverter. While the value of the highest cooling load (cooling load) is 1043,86 Watt is the variation of frequency inverter 24 Hz. While the value of evaporative heating coefficient (hevap) is the lowest 940,834 W / m2K at 16 Hz frequency, the lowest cooling load capacity value is 410,622 Watt at 16 Hz frequency.