Abstarct: The blades are the main components of the gas turbine, which are affected by different failure mechanisms due to their harsh working conditions. At the higher entrance gas temperatures, the turbine efficiency increases. In such conditions, directional solidification (DS) and single crystal (SX) blades are used due to their greater resistance to creep and fatigue. The first step in the casting of these types of blades is the production of ceramic cores. These cores must have suitable bending strength at ambient and high temperature, chemical stability, low thermal expansion coefficient and suitable porosity for easy leaching. Alumina-baxsed ceramic cores are used to create air-cooled paths in DS and SX blades, as they have high thermal stability and good strength at the high casting temperatures of these types of blades. In this research, alumina baxse cores with zircon as a novel additive was produced. The effect of the zircon and magnesia additives, sintering temperature and alumina particle size distribution was investigated to achieve a suitable combination of strength and porosity. A Taguchi experimental design was done to find the optimal production conditions. The samples were injected using the ceramic injection molding. Sintering of the injected samples was done in three different temperatures of 1350, 1400, and 1450°C. The porosity, density and leaching ability were measured and bending strength tests were done at the room temperature. 25% zircon, 1.5% magnesia, alumina particle size distribution of 30% MR70- 70% MR42, and sintering temperature of 1400°C were obtained as optimal production parameter levels. It was found that the particle size has a great effect on the strength and porosity. The smaller the particle size, the more binder we need. As a result, the strength decreases. Magnesia has a significant effect in preventing grain growth and increasing strength. Zircon reduces the thermal expansion of the samples, in addition to high durability and strength. In the final step, more detailed analysis was done on the sample produced in the optimal conditions. The bending strength of this sample at room and 1200°C temperatures was 91.055 MP and 100.152 MPa, respectively. Also, apparent porosity and sintering shrinkage of the sample produced in the optimal conditions were obtained 31% and 0.74%, respectively. The results showed that the core material has suitable properties to be used in the casting of directional solidification (DS) and single crystal (SX) turbine blades.