The invention belongs to the technical field of annular furnace equipment and discloses an online restoration method for a lower track of a rotary type annealing furnace. The online restoration method for the lower track of the rotary type annealing furnace comprises the steps that a supporting roller set located below the track is leveled, and the vertexes of all supporting rollers are made to be located in the same plane; the track face heights of all long tracks and all short tracks forming the track are measured; the long tracks and the short tracks with the track face heights exceeding the error range relative to the reference height error are screened out and serve as to-be-adjusted tracks; one supporting roller in the supporting roller set below the track is dismantled, and a track adjusting space is formed; a trolley of the rotary type annealing furnace is driven to move, and the to-be-adjusted tracks which are screened out are moved to the track adjusting space; the track face heights of the to-be-adjusted tracks are adjusted; and when adjustment of all the to-be-adjusted tracks is completed, the dismantled supporting roller is installed. The method can conveniently and fast maintain and adjust the track below the annular furnace.