The invention discloses an online real-time calculation and evaluation method for an electronic belt scale. With a material signal of an electronic belt scale as a triggering condition, a weight collection value, a speed collection value, an instantaneous flow collection value and an accumulated weight collection value that are outputted by the electronic belt scale are collected and an instantaneous flow calculation value and an accumulated weight calculation value are calculated; and a ratio of a collection point to total collection points of the instantaneous flow collection value within upper and lower limits of the instantaneous flow calculation value and a ratio of a collection point to total collection points of the accumulated weight collection value within upper and lower limits of the accumulated weight collection value are calculated to obtain qualification rates of the instantaneous flow collection value and the accumulated weight collection value. According to the method disclosed by the invention, the real-time monitoring of the weighing accuracy of the electronic belt scale is realized and the weighing error risk is estimated; alarm shutdown can be conducted in timethrough real-time judgment; the damage of the production material quality is reduced; and the process monitoring strength of the electronic belt scale is greatly enhanced.