In this paper, the authors propose ultra-small cylindrical helical antenna structure (about 0.01λ) combined with parasitic element used in auto monitoring system vapor pressure in automobile tires. With proposed helical antenna structure, the author will replace currently used loop antenna and studied cylindrical helical antenna. The new feature of the proposed antenna pattern is using parasitic element to not only impedance matching but also without using tap feed. The author optimizes the resonant structure and calculates some parameters such as input impedance, gain factor, voltage standing wave ratio, the current antenna's distribution and radiation pattern when the antenna is placed in free space. The proposed antenna has simple structure and it is suitable for TPMS.