The invention discloses an LTCC (Low Temperature Co-Fired Ceramic)-based passive LC (Inductive-Capacitive) humidity sensor. The LTCC-based passive LC humidity sensor comprises thirteen layers from top to bottom, wherein the layers with odd numbers are all ceramic dielectric layers, the layers with even numbers are all metal layers, the second capacitance metal layer is exposed out of a window of the first dielectric layer, so that the capacitance layer can sense the humidity, the fourth, sixth, eighth, tenth and twelfth metal layers are all inductance metal layers, and two ends of inductors positioned in the fourth and twelfth metal layers are connected with two ends of the second capacitance metal layer by through holes to form a parallel LC circuit. The LTCC-based passive LC humidity sensor is realized by utilizing an LTCC technology, and can be used for effectively reducing the production process and greatly reducing the production cost, and a quality factor of a ceramic material is high, so that the loss of the circuit is low. More importantly, the LTCC ceramic material is good in stability and not sensitive to environmental changes, and a ceramic sintering body is compact in structure and low in moisture permeability, so that the sensor can be applied in a high-humidity environment without encapsulation.