Electronic oil pressure sensor installed in the engine of the main road, when the engine running, pressure measurement device to detect the oil pressure, the pressure signal into electrical signals sent to the signal processing circuit, a voltage amplification and current amplifier, through the pressure signal of signal lines will be enlarged to connect to the oil pressure indicator, and change the oil pressure indicator inside by the current ratio of 2 coil, thus indicating the engine oil pressure. The pressure signal amplified by voltage and current is also compared with the alarm voltage set in the alarm circuit. When the voltage is lower than the alarm voltage, the alarm circuit will output the alarm signal and light the alarm lamp through the alarm line.