Abstract: Analysis and evaluation for criticality accident of the cylindrical solution system has important academic significance and value of the engineering. In order to realize the analysis and evaluation of this system, this paper studies the mechanism of the development of the nuclear criticality accidents, and developes a simulation and analysis program CAACS for the criticality accidents of the cylindrical solution system independently, which provides the technical means of accident analysis for the transformation and construction of subsequent commercial fuel reprocessing plants plant, and lays the foundation for subsequent critical transient studies.