The invention discloses an open flash point detection device of petroleum and petroleum products, mainly comprising a high voltage ignition anode, a gas ignition arm, a sample detection cap, a flash point detection anode and cathode, a sample temperature sensor and a control circuit, wherein the ignition anode and the ignition arm are arranged above the panel, a cup rim of the detection cap is arranged on the panel, the detection anode and the detection cathode are respectively arranged at the center and the circumference of the cup rim of the detection cap, three uniformly distributed detection heads are arranged on the detection cathode, an ignition detection sensor is arranged nearby the ignition anode. The device is used for detecting the open flash point of the petroleum and the petroleum products, realizes automatic detection through an electronic circuit and a program control, operation is convenient, detection is reliable, detection precision is high, which satisfies requirement of international rules.