The invention provides a method for recycling cellulase from marine aspergillus niger fermentation liquor. An improved tannin precipitation method is utilized to separate and extract cellulase which is generated by cellulase generating microbial fermentation, a vacuum freeze drying method is utilized to prepare a powdery cellulase product, and the recycling rate of the cellulase can reach 90 to 95%; thus, the method has the advantages of short used time, small energy consumption, simpleness in operation and high cellulase recycling rate. The method disclosed by the invention solves the problems that a stage of separating and extracting the cellulase in the whole technology of preparing ethyl alcohol from lignocellulose has overhigh cost and complexness in operation and is suitable for industrial large-scale preparation of the cellulase recycled from marine aspergillus niger. The marine aspergillus niger chosen by the method disclosed by the invention has the characteristics of salt resistance, rich enzyme systems, high expression quantity and strong secretion capacity. The method disclosed by the invention is reasonable in design, simple and practical to operate, low in equipment cost invest, high in yield and suitable for industrial production of separating and extracting the cellulase in large scale.