Abstract: In China pine wilt disease occurred in many places.Several kinds of nematodes were found in the wilt tree wood from 11 provinces.Four prominent species were identified.They are Bursaphelenchus mucronatus,B.xylophilus,Cryptaphelenchoides propora sp.n.,and Cylintrotylenchus pini gen.n.,sp.n.,Cryptaphelenchoides propora sp.n.differs with C.macrobulbosus by not having stylet basal knobs,excretory pore anterior to hemizonid,vagina not at right angles to the body,spicules end curves.Cylindrotylenchus gen.n.resembles Anguillonema but differs in similar six lips,oesophagus very long,oesophagointestinal cells absent,excretory pore near posterior of isthmus,excretory duct distinct.The type species of Cylindrotylenchus gen.n.is C.pini sp.n..Body cylindrical,head not offset.Oesophagus very long,b=3.1—4.0(for female) and 4.5—7.4 (for male);isthmus narrow;terminal bulb long and clubshaped.Post-vulval sac present.Female tail cylindrical to a rounded end;anus indistinct.Male tail with large enveloping bursa;spicules and gubernaculum tylenchoid