Poplar（Populus euramericana cv.’I-214’） veneer with thickness of 0.7 mm was dyed by reactive KN-R blue dyestuff.The influence of dye consumption,as well as technical factors such as dyeing temperature and time,on dyeing effectiveness was evaluated.It was found that the dyestuff quantity absorbed by the veneer increased as the concentration of the dyeing solution rose from 0.01% to 0.02%.Under a certain condition,neither dyeing temperature nor dyeing time had much effect on the veneer,so optimum parameters were determined as follows: concentration of KN-R of 0.20%,dyeing temperature at 40 ℃ and a duration time for 1 h.