Based on the principles of autocatalysis and the theory of entropy, this paper tries to discuss and attest the autocatalytic mechanism in systems which cause general S curve.

• 运用熵理论和自催化原理对系统发展过程中普遍存在的S型曲线的成因进行了论述和证明,指出系统出现S型发展曲线是由系统的自催化机制和系统的限制因素共同作用引取。