Constructing artificial algal crusts by means of cyanobacterial inoculation could promote growth and development of biological crusts on sand dunes in desert regions and restoration of the whole desert ecosystem, and hence is considered as an effective approach to desertification control. However, in the course of constructing artificial algal crusts, the inoculated cyanobacteria or formed crusts are susceptible to various environmental stresses, mainly drought in the desert regions. An in-lab experiment was carried out to have artificial algal crusts exposed to drought and rehydration, and to explore their effects on crust biomass, exopolysaccharides and photosynthesis of the crusts. It was found that drought for one day could provisionally promote secretion of crust cyanobacterial exopolysaccharides (p<0.05). Once the crusts were completely dried, cyanobacteria of the crusts stopped all their metabolic activities, and biomass and exopolysaccharides content of the crusts remained at a certain relatively steady level. After rehydration, crust original fluorescence Fo got recovered quickly and reached the maximum within 10 min. Afterwards, Fo decreased gradually and crust photosynthetic activity (F_v /F_m) increased and leveled off steadily in line with the function y=ax/(b+x). In addition, under different water conditions, crust photosynthetic activity increased with the increasing crust water content, but crust net photosynthesis (P_n) first increased and then decreased with the increasing crust water content, showing a unimodal variation pattern. This study suggests that the regulation of crust cyanobacteria in metabolism plays an important role in the adaptation of artificial algal crusts to arid desert environmental conditions. The findings may help us further understand how cyanobacteria or cyanobacterial crusts adapt to drought stress, and provide theoretical basis and practical lessons for construction, maintenance and management of artificial algal crusts in desertification control.