In the process of develop oil field, the main way to evaluate corrosion condition is to monitor the corrosion situation under the oil well, which can help guide and verify the implementation and the effect of the whole anticorrosion engineering. The corrosion monitoring system of DCMS is based on the principle of resistance, and the corrosion rate can be measured by the calculation of the loss of metal. The results show that DCMS can be used to monitor the corrosion speed rate in a realtime, and have the characteristics of high sensitivity, widerange application and so on, it can also provide intuitive test data that aim at the corrosion of underground which depends on the good predictability.