We present the third MAXI/GSC catalog in the high Galactic-latitude sky (\(|b| > 10^\circ\)) based on the 7-year data from 2009 August 13 to 2016 July 31, complementary to that in the low Galactic-latitude sky (\(|b| < 10^\circ\); Hori et al. 2018). We compile 682 sources detected at significances of \(s_{\rm D,4-10~keV} \geq 6.5\) in the 4--10 keV band. A two-dimensional image fit based on the Poisson likelihood algorithm (\(C\)-statistics) is adopted for the detections and constraints on their fluxes and positions. The 4--10 keV sensitivity reaches \(\approx 0.48\) mCrab, or \(\approx 5.9 \times 10^{-12}\) erg cm\(^{-2}\) s\(^{-1}\), over the half of the survey area. Compared with the 37-month catalog (Hiroi et al. 2013), which adopted a threshold of \(s_{\rm D,4-10~keV} \geq 7\), the source number increases by a factor of \(\sim\)1.4. The fluxes in the 3--4 keV and 10--20 keV bands are further estimated, and hardness ratios (HRs) are calculated using the 3--4 keV, 4--10 keV, 3--10 keV, and 10--20 keV band fluxes. We also make the 4--10 keV lightcurves in one year bins for all the sources and characterize their variabilities with an index based on a likelihood function and the excess variance. Possible counterparts are found from five major X-ray survey catalogs by Swift, Uhuru, RXTE, XMM-Newton, and ROSAT, and an X-ray galaxy-cluster catalog (MCXC). Our catalog provides the fluxes, positions, detection significances, HRs, one-year bin lightcurves, variability indices, and counterpart candidates.