Downlink channel estimation in millimeter-wave (mmWave) frequency division duplex (FDD) massive multiple input multiple output (MIMO) systems is investigated in this letter. Considering the sparse scattering nature of the mmWave channels, the estimation problem is formulated as a sparse parameter estimation problem. A low-complexity orthogonal matching pursuit (OMP) estimation algorithm is proposed by exploiting the inherent correlation in the signal angular domain and the statistical scattering information. Analysis and simulation results verify that the proposed algorithm can achieve more than 90% complexity reduction with comparable or even better estimation performance than the existing OMP-based algorithms.