Abstract: The hydrocarbon metering system for a single well was mainly composed of parallel large and small range flowmeters and PLC controller. In the actual measurement process, PLC controller controlled program according to design requirement and flow size. Hydrocarbon metering system could automatically switch to small range, wide range or the combination of both, which effectively expanded the scope of flow measurement (range ratio) and met the need in the accurately calculation of oil and gas. This system provided accurate and reliable production data about reservoir change, well production condition and hydrocarbon exploration scheme. The method was mainly used in oil and gas field development in the process of multi well concentrated metering system, and other wide range flow measurement engineering.