The invention discloses a simple method for calculating the short-term maximum allowable overload current of a submarine electric power cable, and relates to an overload current calculating method. An existing method of calculating the short-term maximum allowable overload current of a cable refers to standards, needs plenty of parameters and complex formulas, is complex in calculation process, and can hardly provide an accurate result within a short period of time. The method includes the following steps of obtaining environment parameters, obtaining structural parameters and electrical parameters of a submarine cable body, obtaining an initial current value I1 of the submarine cable through online monitoring, calculating the initial temperature of a conductor according to the IEC 60287 standard formula, obtaining the short-term overload time tm according to an overhaul or schedule instruction, and calculating the maximum allowable overload current I2 within the short-term overload time tm through the formula (please see the formula in the specification) when the short-term overload time tm is smaller than set time. According to the technical scheme, few parameters are required for calculation, and the calculation process is easy, convenient and rapid. The shorter the overload time of the submarine cable is, the higher the reliability of the calculation result is.