Abstract: Eucalyptus is one of the main raw material for pulp. 4-coumarate: coenzyme A ligase is one of the key enzymes in the biosynthesis of lignin monomer. Inhibited the expression of 4CL gene can effectively reduce the content of the lignin in plants. The plant expression binary vector with glycine rich protein (GRP1.8) fused antisense 4-coumarate: CoA ligase (4CL1) gene from Populus tomentosa was transformed to Eucalyptus grandisE. ophylla. Nine transgenic plants were obtained by kanamyic resistant selection and PCR amplification selection. The 4CL1 enzyme activity of transgenic plants in tissue culture decreased up to 44% compared with wild-type plants. The klason lignin content of regenerated Eucalyptus seedlings in greenhouse decreased up to 16%.