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Using a column crystallizer to separate and purify naphthalene in the continuous multistage countercurrent fractional operation.The principle and characteristic of process are introduced.A large amount of experimental work has been done on the crystallization process in a D=50×1350 mm column.The effects of operation conditions including the composition of feed,reflux ratio and the bed height of crystal on crystallization were systematically studied.The experiments showed that the purity of product can easily exceed 99.0% at rang of feed composition among w=81.34%~90.85%,reflux ratio among 1.88~5.14,the crystal bed height among 300~600 mm.The purity of product even achieved 99.99% in sometimes of experiment.The energy consumption of this process can make use of the lower level energy such as used heat,waste heat and after heat etc in chemical plant and its operation cost is much lower than distillation process.A mathematical model is developed which considers axial dispersion and mass transfer between the liquid adhering to the crystals and the bulk liquid.The model satisfactorily coordinated with experiment data.