Abstract: To meet the RFID tag requirement of the miniaturization and space compressibility, we propose a novel non-uniform pitch spiral UHF_RFID tag antenna. At first, according to the classical isometric helical antenna theory, we dis cuss the non-isometric helical antenna radiation mode. Then, put forward a multi-media filling construction based on the ra diation characteristics of electromagnetic waves on different dielectric layers, which make the multi-media label antenna come true and improve the radiation efficiency. At last, the actual non-uniform pitch spiral antenna measurement data can keep up with the result of CST software simulation and optimization. the real test result shows that the return loss can keep under - 10dB in 871 ~ 928 MHz which can cover our country UHF_RFID bandwidth 860 ~960MHz,the biggest radiation gain can reach 2. 5 dBi, the 3dB lobe width is about 86 degrees, and the over size of the proposed tag antenna is only 64mm×Φ6mm.