We present the third MAXI/GSC catalog in the high Galactic latitude sky (|b|>10{deg}) 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{deg}) (Hori+ 2018ApJS..235....7H). We compile 682 sources detected at significances of s_D,4-10keV_>=6.5 in the 4-10keV 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 4-10keV sensitivity reaches ~0.48mCrab, or ~5.9x10^-12^erg/cm^2^/s, over half of the survey area. Compared with the 37-month Hiroi+ (2013, J/ApJS/207/36) catalog, which adopted a threshold of s_D,4-10keV_>=7, the source number increases by a factor of ~1.4. The fluxes in the 3-4keV and 10-20keV bands are further estimated, and hardness ratios (HRs) are calculated using the 3-4keV, 4-10keV, 3-10keV, and 10-20keV band fluxes. We also make the 4-10keV light curves in 1-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, as well as an X-ray galaxy cluster catalog (MCXC). Our catalog provides the fluxes, positions, detection significances, HRs, 1-year bin light curves, variability indices, and counterpart candidates.