Millimeter wave (mmWave) communication has become a promising key technology of the fifth generation (5G) communication systems, and gained extensive interests. In this paper, we examine 60 GHz mmWave channels in an indoor office environment by means of ray tracing method. Based on geometrical optic (GO) and uniform theory of diffraction (UTD), ray tracing method uses computer simulation to approximate the radio wave propagation. The accuracy of ray tracing based simulation is guaranteed by a very detailed three-dimensional (3-D) environment model and proper material electromagnetic parameters. The simulation results including power delay profile (PDP) and normalized power angular spectrum (PAS) are compared with the channel measurement data which is processed by the space-alternating generalized expectation-maximization (SAGE) estimation algorithm. Good agreements between simulated and measured properties of dominant paths are achieved in both line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. The comparison results indicate that ray tracing can be a useful and reliable method for characterizing 60 GHz channel properties.