The invention provides a multi-weighing-sensor on-line calibration method for a mass measurement platform of an unmanned plane, and the method comprises the steps: 1, arranging n measurement regions at places, corresponding to the weighing sensors, at the upper side of the measurement platform; 2, enabling weights with the known values to be placed in the measurement regions, placing the weights in one measurement region at each time, collecting voltage values measured by all weighing sensors, and carrying out the collection of voltage values for n times; 3, calculating product coefficients which are needed for the conversion from the voltage values of all weighing sensors to weight values according to the voltage values collected at step 2 and the known values of the weights; 4, achieving the measurement calibration of each weighing sensor at the lower side of the measurement platform according to the obtained product coefficients obtained at step 3, thereby achieving the on-line calibration of the measurement platform. The method provided by the invention is simple in operation, is high in calibration precision, and is high in universality.