Abstarct: In this research, ceramic core with different percentages of ZrO2, SiO2, Al2O3, potassium feldspar and diatomaceous earth were made by injection molding or CIM method. Various evaluations such as shrinkage test, bulk density test, three-point flexural test and leachability test were performed on the constructed ceramic cores. The results showed that ceramic core with 0.8% by weight of potassium feldspar and 18 minutes of leaching time is the optimal composition. Also, by adding potassium feldspar, the density and shrinkage of silica ceramic core first increased and then decreased, and by adding potassium feldspar up to 0.8% by weight, ceramic core strength increased to 11.8 MPa and then decreased by adding more potassium feldspar. Also, with the increase of diatom, the shrinkage of ceramic core increased and the density decreased. On the other hand, with increasing amounts of diatoms, ceramic core strength reached 4.8 MPa and leaching time decreased to 4 minutes. Considering the acceptable strength and at the same time the leaching time of the sample with 3% by weight of diatom, the optimal sample was selected. X-ray pattern was used to identify the crystalline phases in the samples and scanning electron microscope was used to check the morphology and surface shape of the samples. EDX pattern was also used to detect the purity and absence of any chemical impurity.