The invention discloses a LTCC-based planar transformer and a manufacturing method thereof. The method comprises the following steps: S1, preparing an upper substrate, a lower substrate and a plurality of middle substrates, which all employ an LTCC (Low Temperature Co-Fired Ceramic) material raw ceramic chip with the first magnetic conductivity; S2, forming a hole in at least one middle substrate;S3, manufacturing primary and secondary electrode patterns on the plurality of middle substrates, and performing the filling of the holes to form a plurality of electrode layers; S4, putting an LTCCmaterial with second magnetic conductivity in areas where the primary electrodes and the secondary electrodes of the plurality of electrode layers are mutually inducted and overlapped to form a plurality of filling electrode layers, wherein the second magnetic conductivity is greater than the first magnetic conductivity; S5, laminating the plurality of filling electrode layers, the upper substrateand the lower substrate, and carrying out glue discharging and sintering to form the LTCC planar transformer, in which the LTCC material with the first magnetic conductivity and the LTCC material with the second magnetic conductivity are co-fired and then tightly combined to form an intermediate magnetic conductivity material with the magnetic conductivity being between the first magnetic conductivity and the second magnetic conductivity. The coupling coefficient of a planar transformer can be effectively improved, and the primary leakage inductance and the secondary leakage inductance of theplanar transformer are reduced.