3D printing technology with design flexibility can produce soft sensors more efficiently than traditional manufacturing technology, however, the improvement of printing accuracy is an urgent problem to be solved. The rapidly UV-curable speed of the material is helpful to solve the problem. Herein, the new polymeric resins with good softness and rapidly UV-curable speed were prepared, and then a high printing accuracy soft sensor was prepared by imitating embedded 3D printing methods with the resins as components. In synthetic resin, the polybutadiene (PB) with high flexibility was designed as the flexible main chain, pentaerythritol triacrylate (PETA) with multi photosensitive groups as UV-curable groups and oxalyl chloride (COCl) with no forming hard segments as the linker between PB and PETA. The resins have rapidly UV-curable speed that can maintain the shape within 1 s, basically cured within 5 s. The cured samples of resins have small Young’s modulus and good softness similar to biomaterials, and the T_g is around −60 °C. The soft sensors based on the resins have the characteristics of high printing accuracy, good sensitivity, versatility, and a wide temperature range of application, and could be integrated into many joints on the body to detect our motions.