Abstract: The MCWA18 strain of Paecilomyces lilacinus was demonstrated as a highly effective strain to control root knot nematode Meloidogyne incognita. Results of the petri dish test showed 92.6% of the eggs were parasitised by the fungus 18 d (7 days at 18 ℃ plus 11 days at 25℃) after inoculation. A pot experiment was conducted in the glass house to evaluate the biological control effects of the MCWA18 strain of P. lilacinus against M. incognita on tomato as compared with the nematicide. After 93 days, the fungus solid culture treatment at dosages of 5g/m 2 and 10g/m 2 reduced the larval population in the soil around the roots by 62.3% and 66.9%, respectively increased the plant height by 17.2% and 49.6%, and increased the fresh mass weight of the above ground part of the plants by 100.0% and 145.9%, while in the nematicide treatment using ethoprophos (Mocap 10G at 4.5g/m 2) the population of larvae on tomato plant was reduced only 30%.