The invention discloses a preparation method of an aluminum 
nitride raw 
ceramic sheet for high temperature co-fired 
ceramic. The preparation method comprises the following steps: 1) loading a grindingball; 2) disposing 
slurry; 3) performing primary 
grinding; 4) configuring 
casting slurry; 5) performing secondary 
grinding; 6) performing vacuum defoaming; 7) 
casting, wherein the 
casting slurry subjected to vacuum defoaming is transferred to a casting 
machine for casting operation, and the thickness of a 
green tape is controlled within a range of 0.05 to 1 mm; and 8) 
cutting. The 
raw material does not contain toxic components such as 
benzene, 
ketone and 
aldehyde, and organic toxic and harmful substances and waste liquid are not generated in the production process, thereby reducing environmental 
pollution. The raw 
ceramic sheet produced by the method has high strength, good 
thermal conductivity and uniform density, and is less prone to deformation, high in 
punching printing precision andgood in flatness and has good shrinkage matching with metallized slurry in the production process of high temperature co-fired ceramics. The 
film coating operation is not needed in the production process, the problems of softness, difficult 
processing, 
high probability of offset filling printing and lamination misalignment and the like are solved, and the production efficiency is improved while the production cost is lowered.