Plastic resin is used to connect barrel to nozzle in injection unit. screw stroke, injection cylinder body pressure and barrel temperature are the most important terms of injection unit, interval linearity and repeatability to each term are analyzed here. Barrel temperature is analyzed according to the repeatability of the thermocouple at 150℃ using precise oven. The result temperature is within ±0.5℃ The standard deviation of barrel temperature shows 0.12~0.15, which being present as accurately during the test. Also measurement uncertainty was calculated regarding temperature, humidity factors in order to verify the test consistency.