The invention relates to a positioning method of a ceramic core of a blade, and particularly relates to a positioning method of a ceramic core of a turbine blade with a block-cast cover plate structure. According to the following technical scheme of the invention, the positioning method of the ceramic core of the turbine blade with the block-cast cover plate structure comprises two processes of positioning a ceramic core of the turbine blade with the block-cast cover plate structure in a blade shape mould and positioning the ceramic core in a blade wax mould in a ceramic shell. The invention provides a positioning method of the ceramic core of the turbine blade with the block-cast cover plate structure. Positioning of the ceramic core in the blade shape mould and in the ceramic shell is comprehensively considered in a precision casting process, the consistency of an inner outline and an outer outline is ensured, and the distance between the top end of a cover plate of the blade and a reference surface of the blade can be enabled to accord with the tolerance requirement.