The link between the intergalactic medium (IGM) and galaxies is a key to understand the evolution of baryonic matter and galaxies. Although several observations have identified the presence of IGM-galaxy connection up to several tens comoving Mpc using Lyα forest absorption as a tracer of IGM HI, the understanding of their variations over galactic properties, such as mass, SFR and population, is still limited. In order to shed more light on the connection, we perform cross-correlation analysis between galaxies and IGM HI evaluated from simulations and observations. For simulations, we use the light cone from cosmological hydrodynamic simulations, GADGET3-Osaka. For observations, we use publicly available IGM HI 3D tomography data, CLAMATO (Lee et al. 2016, 2018), and several galaxy catalogs. In this talk, we will present the similarity and distinction of the correlation functions, and discuss Mpc scale HI environments around galaxies depending on their properties.