The invention relates to a fused deposition modeling printing method for oral cavity medical products with proper precision. The method includes the following steps: 1) designing STL data of an oral cavity medical product on oral cavity medical CAD software; 2) opening the STL data, adjusting arrangement angle of the STL data so that the included angles between all the to-be-printed aesthetic or functional surfaces in the STL data and the Z-axis is less than 45-70 degrees; 3) setting support critical angle as 45-70 degrees; 4) setting printing layering thickness as 0.05-0.6 mm; 5) performing spiral printing along the surface of the data or performing printing in X-Y horizontal direction; 6) selecting a print head being 0.2-0.8 mm in inner diameter; 7) setting printing internal filling ratio as 20-100%; 8) setting printing wall thickness as the optimum width that is printable in single feeding by the print head; 9) generating a layering printing code and inputting the layering printing code to printing control software, and starting printing. The method is suitable for high-precision and high-efficiency fused deposition 3D-printing modeling process for individual trays, guide plates and work models in oral cavity medical application and castable or injection-moldable wax molds of various types of false tooth with a proper precision.