In this paper the features of information asymmetry and information model under the model of management by construction agency in project invested by government are analyzed, the information asymmetry in the main bodies of construction agency in the project invested by government is studied. Especially the advantages and weaknesses in information among government consignor, consuming unit and construction agency are analyzed. A dynamic model of incomplete information among government consignor, consuming unit and construction agency has been set up,a game theory analysis on the actions about the main bodies of construction agency in the project invested by government is carried out.