On the development of the superconducting helical coil, it is important to examine the mechanical behavior of the coil and the evaluation of the coil rigidity at liquid helium temperature. The helical coils in the Large Helical Device are subjected to high electromagnetic force of about 10MN/m. This paper deals with the mechanical behavior and the compressive rigidity of the superconducting coil pack under compressive load at liquid helium temperature. Finite element method is used for the numerical analysis of the composite structure of the coil pack. The numerical results of displacements and strains are obtained and compared with the experimental results. The validity of numerical techniques for evaluating the rigidity of the coil pack is also examined.