A lathe suspension rod self-locking device with a reasonable structure is characterized by comprising a suspension rod, a pressure cover, a self-locking rack, a bolt, a first bearing group, a flange, a second bearing group, an adjusting pad, and a locking nut; the suspension rod uses the bolt to arrange the self-locking rack and the flange on the side face of the suspension rod; the self-locking rack uses the bolt to fix the pressure cover; the first and second bearing groups are arranged between the suspension rod and the flange; the first bearing group is above the second bearing group; the second bearing group bottom is locked by the locking nut; the annular adjusting pad is arranged between the second bearing group and the locking nut. The advantages are that the lathe suspension rod self-locking device has the self-locking structure, so an operator can conveniently manually rotate the suspension rod to the needed position, and the suspension rod cannot rotate back, thus improving operator work efficiency.