Abstract: Social risk sources have the characteristics of objectivity，dependence，variety，potentiality and controllability.From the perspective of the basic constituents of social system，risk sources fall into four categories：natural risks，population risks，information risks and institutional risks.And from the subsystem perspective：political risks，economic risks，cultural and educational risks and technological risks.Further classification can also be made from different angles.

Key words: social risk, social risk sources, risk control, society construction, society management