This paper explores the ways in which public private partnership manages public parks by focusing on collaboration between NPO organization, which operates public park management, and BID organization, which attempt to improve urban environment within the area. Through the research, the following three points are cleared. The purpose of the NPO’s establishment affects the way to collaborate between NPO and BID. Union Square BID financially support the NPO organization. Park’s spatial structure determines NPO’s activities and the way to collaborate with BID organization.