The invention provides a fast pyrolysis method for producing oil from fruit core waste. A downdraft type fast microwave pyrolysis reaction device is controlled. The target pyrolysis temperature is setto 500-750 DEG C, the target catalytic temperature is set to 200-500 DEG C, the microwave power is regulated to 1000-9000 W, the feed rate is set to 5-50 kg/h and the stirring speed is set to 20-120r/min. When the pyrolysis temperature and the catalytic temperature reach the set target values, fruit core waste is continuously added into a microwave reaction chamber through a spiral feeder, and astirrer stirs the fruit core waste up and down; pyrolysis residues are discharged into a residue storage device; pyrolysis steam is subjected to catalytic reforming, biological fuel oil enters a liquid collector, and biological fuel gas is collected by a gas collector. The method can achieve continuous operation, is suitable for industrial production and short in reaction time, has few side effects, pyrolysis steam can be subjected to effective catalytic reforming, and the quality of biological fuel gas is improved.