The utility model relates to an oil slurry heat reutilization system of a catalytic fractionating tower. The oil slurry heat reutilization system is mainly used for solving the problem that oil slurry heat at the bottom of the catalytic fractionating tower is excessive and can not be fully utilized in the prior art. The oil slurry heat reutilization system is characterized in that the tower bottom of the catalytic fractionating tower (1) is connected with an oil slurry pump (2), and the oil slurry pump (2) is sequentially connected with an oil slurry heat exchanger (3) and an oil slurry steam generator (4); the oil slurry steam generator (4) is connected with an oil slurry intermediate heat exchanger (5), and the oil slurry intermediate heat exchanger (5) is further respectively connected with the lower part of the catalytic fractionating tower (1) and a reboiler (6) of a desorption tower; the reboiler (6) of the desorption tower connects a cooler (9) to the middle and upper part of the catalytic fractionating tower (1) through a pipeline; and a pump is connected on the pipeline connecting the oil slurry intermediate heat exchanger (5) with the middle part of the catalytic fractionating tower (1). The oil slurry heat reutilization system of the catalytic fractionating tower can reasonably utilize the heat of the system and reduce the energy consumption of the device.