The results of the researches have shown that microstructure of the multicomponent suspension of flaxseed additive is structured. Microstructure includes particles of flaxseed, globules, aggregates and has a cellular microstructure. The formation mechanism of the suspension microstructure of flaxseed additive was proposed, which includes such stages as a formation of globules, an aggregation of globules in aggregates, the formation of areas with cellular structure.