The sintering additives have directly influenced on the phase composition such as crystal phase, glass phase and pore, and then affected the mechanical properties of porcelain material. The additives (ZnO, TiO2, and ZrSiO4) with 2% were added respectively into the billets of porcelain, followed by manufacturing the mud, dehydration, vacuum pressing, extruded reagent strips and sintering simultaneously in industrial kiln with the products. The reagent strips were tested for their bending strengths. Meanwhile, the scanning electron microscopy (SEM) was adopted to observe the microstructure, and X ray diffraction (XRD) was used to determine the phase. The results show that sintering additives can significantly improve the bending strength of the reagent strips, reduce the porosity of the samples, improve the density and reduce the amount of primary mullite dramatically, while secondary mullite developed and intertwined with small amounts of quartz and cristobalite phase.