The preparation of nanocrystalline cellulose using crops and agricultural residues has attracted wide attention recently. The primary composition of agricultural fibers was introduced. Research progress of nanocrystalline cellulose prepared from crops and agricultural residues was reviewed in terms of raw material kinds, preparation method, properties and application of nanocrystalline cellulose. The main problems in terms of dimensional measurement, surface modification, preparation technology and application were analyzed. The corresponding solution ways were put forward. The preparation of nanocrystalline cellulose is a high value-added application for crops and agricultural residues.