The Large High Altitude Air Shower Observatory (LHAASO) as a new generation of cosmic ray experiment with unprecedented sensitivity is under construction, and the Water Cherenkov Detector Array (WCDA) is one major component aiming at TeV $\gamma$ rays. In order to sufficiently understand the prospect of searching for TeV $\gamma$-ray sources with WCDA, one-year observing ability of WCDA to TeV $\gamma$-ray sources in TeVCat is presented in this paper. There are 56 out of 128 $\gamma$-ray sources in the $45^\circ$ view of WCDA would be observed at the middle energy of 1 TeV. Most of them are galactic sources, and the extragalactic sources are mainly active galactic nuclei (AGNs).