Provided are an apparatus and method for imaging a subsurface using frequency-domain reverse-time migration in elastic medium. The subsurface imaging method represents a frequency-domain imaging condition as convolution of measured data and a partial derivative wavefield. That is, the subsurface imaging method applies a back-propagation algorithm to represent an imaging condition as convolution of a virtual source and a back-propagated wavefield. Then, the subsurface imaging method divides a virtual source vector and the back-propagated wavefield represented by a displacement vector into P- and S-wave potentials through Helmholtz decomposition, thereby providing a new imaging condition.