Decision-making is the beginning of management. Public decision-making with high quality is the precondition of effective public management. Participant-democracy is an important method to raise public decision-making quality but the application of participation was is conditional.The real effect,specialized effect,importance and direct decision-making cost have direct influence on decision-making method and actual effect of decision-making.The quality,ability and work style of the main body of ecision-making are important decisive factors for whether participant-democracy is canied out and its implementation effect.Information storage,legalism degree,expressing mechanism of social interests and total social democracy tradition also have important influence on decision-making quality.Thus,the importance must be attached to suitable conditions of participant-democracy.The effectiveness of public decision-making can be promoted through suitable decision-making ways in scutable time according to practical requirements.