With the constant improvement of the intensive cultivation’s degree, continuous cropping results in decrease of crop production and quality as well as soil-borne diseases which seriously restrict modern agricultural sustainable development. The mechanism of continuous cropping obstacle (CCO) has been one of hot spots at home and abroad. In recent years，a lot of work have been done from many aspects on CCO．However, most efforts are focused on the effect of a single factor while few attentions are paid to the internal interactions and essence of the various factors, which hinder the deep reveal of the real reasons for the occurrence of CCO. The further understandings of the causes of CCO and the interaction relationship between various factors are the basis to control the soil-borne diseases caused by soil-borne pathogens, to alleviate CCO and to realize the zero increase target of pesticide consumption by 2020 in China. This paper reviewed systematically the mechanisms of continuous cropping from the deterioration of soil physiochemical and biological properties, the decrease of plant physiological resistance, self-toxicity of continuous cropping, and the relationship between various factors. The further studies in this filed were also suggested to looking for the theory evidence of mitigation strategies in a safe, environmental and effective way.