This paper aims to clarify the park occupation by homelesses and the mechanisms in Toyama park Tokyo, through the study of their lifestyles. The results are the fallowings 1) The homelesses in Toyama Park could be divided into six groups according to thier attribution, dwelling, employment and diet lifestyles 2) Their reason for occupating the park come from mental and phisical, space and social conditions 3) The park mechanisms of occupation differ according to their lifestyles but the sufficient water supply, free housing expenses and weakness in enforcement are common conditions among all homelesses.