The Large High Altitude Air Shower Observatory (LHAASO) is a hybrid extensive air shower array in Sichuan, China, at an altitude of 4,410 m above the sea level. KM2A is one of the major sub-arrays of LHAASO. It consists 5195 Electromagnetic particle Detectors (ED) and 1171 Muon Detectors (MD), covering an area of about 1.36 ${\rm km}^{2}$. KM2A could detect cosmic rays from 10 TeV to 100 PeV with good element discrimination ability. It will enrich the measurement of the large-scale anisotropy of cosmic rays. This will throw light on the origin of the large-scale anisotropy of cosmic rays, as well as on the cosmic ray origin. The construction of detectors is underway and a part of KM2A array has been operated with 33 EDs since February 2018. In this work, we report the preliminary observation of the large-scale anisotropy using the data collected by the partial KM2A array during 2018.