The invention discloses a method for constructing artificial algal crusts by utilizing mixed algae. The method comprises the following steps of: selecting sufficiently developed algal crusts on the desert, collecting the algal crusts, and grinding the algal crusts after air-drying the algal crusts; sieving bare sand with a 0.2mm sieve, then adding 1 liter of BG11 liquid culture medium to 100g of bare sand, and collecting the algae together with the grains of sand fixed on the algae three weeks later, wherein the inoculum size is 50g dry soil per liter of culture medium, the culture temperature is the room temperature, the illumination intensity is 4000lux, and in the cultured mixed algae, the dominant species are filamentous algae which are mainly microcoleus, lyngbya and phormidium and account for 80% of the total biomass, and species such as oscillatoria, chlorococcum humicola, chlorella, chlamydomonas, Navicula, hantzschia and the like account for 20% of the total biomass; grindingthe collected algae into alga powder after air-drying the collected algae, and putting the alga powder in a refrigerator at minus 20 DEG C; and carrying out inoculation on the bare sand when the soiltemperature is 20 DEG C, wherein the inoculum size is 80g.m<-2>, and the moisture applied daily is 3L.m<-2>. The method successfully avoids the problems of purification and separation of the algae, and has wide applicability.