The invention discloses a real-time yield predicting method for a catalytic cracking device. According to the real-time yield predicting method for the catalytic cracking device, kinetic parameters and device parameters of a catalytic cracking reaction are corrected in real time by processing field real-time data by adopting a data reconciliation technology, and combining an improved differential evolution algorithm, so that the actual operating situations of the device can be described accurately by using a catalytic cracking device mechanism model. The method comprises the following steps: on the basis of a corrected model, analyzing the influence on the yield of a catalytic cracking product caused by key operation / process conditions, such as an operating temperature, a feeding load, a raw material preheating temperature, a reaction pressure, a residue adding ratio, a regenerator temperature, a catalyst-to-oil ratio and the like; performing piecewise linearization according to an influence trend, solving a linear equation to obtain corresponding Delta-Base yield data, associating the operating conditions and the Delta-Base yield data by combining a neural network modeling technology, and establishing a yield agent model, so that the yield data calculating speed is improved; the real-time yield predicting of a continuous catalytic cracking device is realized; a theoretical support is provided for establishing an accurate plan optimization PIMS model.