A packaging method for a tire pressure monitoring sensor includes a step of placing, a step of pouring, and a step of hardening. In the step of placing, a sensing transmission module is put into a cavity of a modeling unit, and a positioning portion in the cavity restricts the sensing transmission module from moving transversely and toward an inner bottom of the cavity. In the step of pouring, a rubber compound is poured into the cavity and fills the cavity. The sensing transmission module is coated by the rubber compound to form a case on the outer surface of the sensing transmission module. In the step of hardening, the case is hardened and integrally formed with the sensing transmission module to form a tire pressure monitoring sensor which is removed from the cavity.