The government held most of the information resources, and the transparency of governmental information is a hotspot that arose widespread concerns in the whole society. Based on the basic information theory, we construct an information matrix. By the thorough study on information matrix, we classify the governmental information into two kinds: governmental affair information and public information that controlled by government. Then from the economic point of view, we analyze the governmental information transparency in the government and the information transparency between the government and public citizen and find the actuality and reasons of opaqueness of governmental information by which we put forward the related countermeasure to improve it in China.