This paper evaluated pulping performance of 3-year-old field-grown transgenic poplar (Populus tremula × Populus alba). The transgenic poplar with anti-sense CCoAOMT had an about 13% decreased lignin content, in which a slight increment was found in S/G ratio. Chemical analysis showed that the transgenic poplar had significantly less benezene-ethanol extractive than that of control wood, but no significant differences were found in contents of ash, cold water extractive, hot water extractive, 1% NaOH extractive, holocellulose, pentosans and cellulose. Fiber assay demonstrated that down-regulation of CCoAOMT expression improved the fiber quality in transgenic poplar. Kraft pulping showed that lower lignin in transgenic poplar led to remarkable improved pulp quality and increased pulp yield.