The invention discloses an organic waste pyrolysis system and a method for disposing organic wastes by the same. The organic waste pyrolysis system comprises a pyrolysis reactor, a screw discharger, a mixing device, a pulverizer and a gasifying and melting furnace. According to the organic waste pyrolysis system, the pyrolysis reactor is used for pyrolysis of organic wastes; the organic wastes are distributed uniformly in the pyrolysis reactor by means of a stirring assembly in the pyrolysis reactor, thus, more sufficient pyrolysis is achieved, oil gas generated in pyrolysis can be released within a shorter time, secondary pyrolysis of the oil gas is suppressed effectively, and yield of pyrolytic tar is increased. Further, semi-coke generated during pyrolysis is mixed with coal and limestone and then subjected to gasifying and melting treatment so that gasified gas with high economic value is obtained.