Abstract: Low temperature co-fired ceramics(LTCC) is the key to fabricate multilayer chip RF low-pass filters, but it is always a difficult problem to realize the matching co-firing of heterogeneous materials. By optimizing the heating rate, holding time and sintering temperature, the influence of sintering process on the shrinkage matching of co-firing was deeply analyzed. It was proposed that the low-pass filter prepared in the chain sintering furnace with the sintering temperature of 860 ℃, the heating rate of 3.5 ℃/min and the holding time of 45 min is proposed. The ceramics matrix and Ag electrode are well co-fired, the insertion loss is reduced from 1.19 to 0.88, the porcelain body intensity is increased from 15.67 N to 32.28 N, and the open circuit rate is reduced from 0.19% to 0.05%, which greatly improves their electrical properties, mechanical properties and reliability, and lays a foundation for the follow-up study on the matching co-firing of heterogeneous materials.