Abstract: A comparison of trophic groups and quantity of nematodes in wilted and healthy turf soil in Yongfeng virescence region of Beijing was done to study the relationship between nematodes and turf wilt. Nematodes in the 0-20 cm depth of soil, whether in wilted or in healthy turf, belonged to 12 genera in 9 families of 5 orders. Harmful nematodes (phytophage nematodes, PPNs) were classified into 5 genera in 4 families of 2 orders and beneficial nematodes (non PPNs) were classified into 7 genera in 5 families of 3 orders. PPNs were absolutely dominant in wilted turf soil and accounted for 87.89% of the total number of nematodes. This was seven times more than other trophic groups (12.05%). Among PPNs, the quantity of nematodes in the genera Helicotylenchus, Pratylenchus and Trichodrus in wilted turf soil were double that in healthy turf soil. The Wasilewska index (WI) indicated that the soil health of healthy turf in Yongfeng virescence region of Beijing, has a potential crisis, while the problem is even worse in the rhizosphere of wilted turf.