An image-based structural health monitoring system and method are disclosed herein. The image-based structural health monitoring system includes a marker image acquisition unit, a marker coordinate calculation unit, a shape function determination unit, and a structural health evaluation unit. The marker image acquisition unit acquires marker images of markers attached onto the surface of a structure. The marker coordinate calculation unit calculates the coordinates of the markers in the marker images. The shape function determination unit determines a shape function by performing spline interpolation based on the calculated marker coordinates. The structural health evaluation unit evaluates the structural health of the structure by calculating the strain or stress of the structure based on the radius of curvature calculated at each location on the determined shape function.