The conceptions of clean water breeding and microalgae water breeding were developed and their characteristics and the precautions to be taken when applied to crab breeding were also discussed in this paper. In addition, the factors affecting the metamorphosis rate of early stages in crab zoea and the corresponding countermeasures were also analyzed. The causes to the different metamorphic rates of Z_1 by using Thalassiosira sp. or Nannochloropsis oculata as starter food in the breeding were compared and the causes to the high mortality of Z_2 and the precautions were analyzed. The results suggested that it be necessary to maintain the concentration of Thalassiosira sp. to achieve the high metamorphosis rate from Z_1 to Z_2 and Z_2 to Z_3 and to save the cost for the growth of harmful algae in the breeding waters were also analyzed. A complete comparison of two breeding methods in the Z_1 metamorphosis rate, production cost and stability etc. was conducted which was of great significance to the guidance of breeding of Eriocheir sinensis.