Influences of some properties of alluvial soil on abundance of trophic groups and genera of nematodes on basis of the canonical correspondent analysis (CCA) are studied. It was shown that two factors, pH and type of alluvial soils, defining all physical and chemical parameters (including soil acidity and moisture) influenced soil nematodes of floodplain forests of a taiga zone. Carbon content in water-soluble organic compounds influenced nematodes abundance less. It was established that the most of nematode genera revealed in alluvial soils were steady to the change of the investigated factors. Genera such as Aphelenchus, Acrobelodes and Pratylenchoides responded more actively on the changes of pH, the others – Mononchus, Dorylaimus, Tobrilus, Eumonchistera, Prismatolaimus, Aporcelaimus, Wilsonema and Cervidellus – on moisture conditions.