The invention relates to a bearing block of a rotary cultivator, and belongs to the field of rotary cultivator accessories. The bearing block comprises a bearing block body, an inner protecting cover and an outer protecting cover. One end of the bearing block body is provided with a cutter shaft protecting bush; the periphery of the cutter shaft protecting bush is provided with a cutter shaft protecting bush guard ring; a bearing installation site is arranged at the other end of the bearing block body and the port of the cutter shaft protecting bush. The bearing block is simple in structure and good in airtightness. Through the cutter shaft protecting bush and the inner protecting cover connected with the cutter shaft protecting bush in a fit manner, sewage and soil can be effectively prevented from entering the bearing block body; through the cutter shaft protecting bush guard ring at the periphery of the cutter shaft protecting bush, weeds can be effectively prevented from winding the cutter shaft protecting bush, and therefore, the problems that a cutter shaft of the rotary cultivator is abraded, the working stability of the rotary cultivator is influenced, and seriously, even a bearing is wound to be locked, so that the bearing cannot work due to the fact that the soil and the weeds are very easy to enter a traditional bearing block are solved. The bearing block of the rotary cultivator is especially suitable for being installed on a paddy field rotary cultivator for use.