The invention provides a tooth filling assisting device. The tooth filling assisting device is characterized in that the assisting device comprises a fixing base located at the upper end, and a clamping device and a separating device are arranged at the lower end of the fixing base in parallel. The clamping device comprises two clamping rods forked downwards. The end of each clamping rod is provided with a transverse fixing and clamping head and a conical gear. The two clamping rods are provided with first adjusting nuts. The distance between the two clamping rods can be changed by rotating the adjusting nuts. The separating device comprises an inserting rod, and an inserting groove is formed in the end of the inserting rod and is internally provided with an inserting piece. A screwing nut which stretches into the inserting groove and is perpendicular to the inserting groove is arranged outside the inserting groove. An inserting piece matched with the inserting groove is formed in the upper end of the blocking piece. The lower end of the blocking piece is in the shape of a cruciate flower. Compared with the prior art, the tooth filling assisting device is unique in structure and good in tooth forming effect, tooth quality can be guaranteed after tooth filling.