This paper introduces an all-fiber temperature sensor based on a parallel Venier Fabry-Pérot interference (FPI) which achieves high sensitivity through a photopolymer self-growing micro-cone and requires only fusion splicing and UV curing for fabrication. The sensor integrates two FPI cavities: one temperature-sensitive cavity formed by a photopolymer self-growing micro-cone, and one thermally stable reference cavity constructed from a silica capillary. Owing to the Vernier effect arising from a slight mismatch in their free spectral ranges, the effective temperature sensitivity is enhanced from 0.25?nm/°C to 1.61?nm/°C, achieving a magnification factor of 6.4. The entire sensor is fabricated in a single step using only standard fusion splicing and UV curing, without requiring femtosecond laser machining or chemical etching. Moreover, the ultra-compact sensor, with a size of less than 1?mm, is not only easy to deploy but also immune to external environmental disturbances, demonstrating potential for a wide range of engineering applications.