Based on the measured topography of the grinding worm, a new approach to modeling the tooth surface topography in continuous generating grinding is studied: (1) Vinyl polysiloxane is used to replicate the surface topography of the grinding worm, and the replicated surface is measured and reconstructed to obtain the real topography. The final surface topography of the grinding worm is generated by mapping the reconstructed topography to the worm surface. (2) The relative motion relationship between the grinding worm and the gear workpiece in the grinding process is analyzed, and the tooth surface topography is generated by the Boolean operation. The simulated results are compared with the experimental results, which validates the correctness and feasibility of the proposed method. The proposed model is used to analyze the tooth surface topography along the gear profile direction. The modeling of tooth surface topography is an innovative work, which is of great significance to the design and manufacture of the gear surface integrity.