The evidentiary effect of certificates issued by units is short of a basis in legal theory. Nevertheless , the certificates issued by units arein common useiniudicial practices . The emergence and development of this phenomenon should be analyzed in the perspective of legal sociology. The social roots which make this phenomenon come into beinglieinthe advent of the unit systemin China . On the one hand, in the unit society, the units supervise and control their me mbers while the me mbers are submitted to and dependant on the units . The social relationship bet ween these two subiects results in a situation that the units become the authoritative spokesmen of the indivi dual witnesses . On the other hand, homogeneity of the units enhances the acceptance of the certificates used in iudicial trials . However , as the unit society of Chinais disintegrating,the phenomenon shows the tendency of a gradual decline . Further more , the transformation of the trial mode has accelerated this progress . Units' certificates applied as evidence ought to vanish in the Chinese iudicial practice , but this will undergo a fairlylong process . In this process , it is extremely crucial for the iudges to adopt a correct attitude towards their "complex of unit" .