Fine Au powders with spherical morphology and good dispersivity were produced. The average particle size is 1 similar to 2m. The influences of constituents on the rheology of organic vehicles were investigated by orthogonal design method. Consequently, the compatible Au thick film pastes for LTCC substrate have been prepared. SEM was carried out to study the sintering behaviors and microstructures of the buried pastes with LTCC substrate. These pastes have high electrical conductivity (less than 3m/sq.), reliable wire bond strength (greater than 9 grams, 25m Au wire) and fine line printability (as small as 80m). The via filling technology was also discussed in this paper.