Abstract: In this study, the static electricity generated by oil itself when it is unloaded from a tanker at a service station is tested and analyzed. To measure the oil level potential of the tanker, the measuring instrument is placed in the middle of the oil level to enable the real-time detection of the potential in the tank when the tanker is loaded and moving. To measure the resistance to ground of the tanker, a megger is used to test the resistance between tank and grounding system directly. To measure the oil charge density in the process of sampling and root control, Faraday cup and digital charge scale are used. As a result, the highest oil level potential is 4 210 V, which is lower than 12 000 V stipulated in GB 6951, tanker resistance to ground basically meets the requirements for leakage resistance of electrostatic conductor (i.e. less than 10⁶ Ω) under GB 12158 and the maximum electric density of the oil is 15 μC/m³ with a small charge. It is concluded that the oil itself produces less static electricity during unloading, corresponding to low probability of electrostatic discharge. The static risk mainly arises from the human body.