Abstract: The purpose of this study was to explore factors influencing the defendants'confession and measures undermining their side-effects.195 police and judicial officers and 185 prisoners were examined by means of Questionnaire,Results revealed:(1) There were 10 factors affecting the disforming of the defendants'confessional motivation while 9 factors affecting the forming of it.Role of those factors thought by police and judicial officers were generally more than that thought by the prisoners,and there were different tendencies between the two kinds of subjects.(2)There were 15 factors that might affect the defendants which were willing to confess but could not confess things according to the facts,and 6 of them indeed had effects.(3)There were 9 measures thought to be efficient to the defendants who would not confess and 10 measures thought to be efficient to the defendants who were willing to confess but could not accurately confess,The ideas between police and judicial officers and prisoners on the validity of measures are complementary.

Key words: defendant, confession, measure, influence, factor