The prestressed concrete girder is a new type of bridge structure. Compared with the traditional concrete girders, its crack resistance has been greatly improved. This type of new girders was used in a certain viaduct in China. In order to probe working characteristics of this type of new girders, some site tests, such as tension-camber test, concentrated load test, uniform load test and mixed load test, were carried out. The results of the tests are analyzed and summed up in this paper.