This paper presents a new LC strain sensor device with an encapsulated serpentine helical inductor. The helical coils of the inductor are formed by serpentine wires to reduce the radial rigidity. Also the inductor is encapsulated by material with high Poisson's ratio. When an axial deformation is applied to this encapsulated inductor, the cross-sectional area of the helical coils will have more evident change due to low radial rigidity and encapsulating material. Therefore, the change of inductance or LC resonant frequency can be enhanced to provide better sensitivity of the LC strain sensor, which are verified by simulated and measured results.