To decrease the wave time difference of pressed planar wave lens, the actual detonation velocity of each subsection of the wave lens was reversely calculated according to the wave plots, and the interfacial curve was designed dividedly based on Fermat′s principle. Then the coordinates of the interfacial curve were fitted out by adjusting the divided interfacial curves. The designed wave lens was manufactured and the blast wave was detected. Results show that our design method can decrease the wave time difference greatly. The wave time differences for Φ100 mm and Φ60 mm wave lens were both less than 0.03 μs.