Hi,Ms.Vicky.
World Expo is no longer a park. It has many entrances, big and small. You can get in from Shang Nan Road of Pudong, the biggest and main entrance of Pudong. Or you can enter from Xi Zang Nan Lu of Puxi, the main gate of Puxi. Or via subway ine 13, exclusive line for World Expo (underground main entrance), or Pu Ming Road (main pass for tourist bus), as well as some small gates such as Zhizaoju Road.