The invention discloses a manufacturing method of a composite ceramic core. The manufacturing method is characterized by comprising the following steps: A, mixing a ceramic core raw material; B, designing and manufacturing a tin alloy middle mold core; C, pressing the ceramic core raw material into a forming mold with the tin alloy middle mold core in a pressure forming machine for hot pressing forming by controlling the pressure intensity in a range of 1 to 20 MPa and controlling the temperature of the mold in a range of 90 to 160 DEG C; D, after the ceramic core is formed, heating the mold to a melting point of a tin alloy to melt the middle mold core and enable the middle mold core to flow out, so as to complete the manufacturing of the ceramic core. According to the manufacturing method disclosed by the invention, by use of the characteristics of low melting point and sufficient intensity of the tin alloy, the ceramic core is enabled to bear mold filling pressure during compressionmolding, so that the ceramic core subjected to the hot pressing forming has high size stability, and the obtained ceramic core is complicated in structure.