Abstract: In order to cultivate large-diameter Eucalyptus grandis ×E. urophylla timber, a twice-thinning trial wasconducted on 10-year-old E. grandis ×E. urophylla stand with the initial density of 1 650 trees per hectare. The firstthinning was conducted 3 years after afforestation, and the second thinning conducted 3 years after the first thinning.Three thinning intensities ( 2 /3, 1 /2, and 1 /3 ) and a control ( no thinning) were arranged. The randomized blockexperimental design was adop ted to study the effects of different thining intensities on the DBN, tree height,individual volume, stand volume and economic benefits of E. g randis ×E. urophy lla. The results showed that themean DBN, individual volume, stand volume and economic benefits of the stand with 645 trees reserved per hectareafter the second thinningwere 23. 6 cm, 0. 552 5 m3 , 356. 379 m3 ·hm-2 , and 293 385 RBM yuan,which increasedby 21. 2% , 54. 2%, 5. 2% and 28. 4% compared with the control respectively, and better than the other thinningtreatments. It also showed that the op timal thinning intensity was 1 /3. The large-diameter E. g randis ×E. urophyllastand with the reserved density of 645 trees per hectare could maximize the DBH, individual volume, stand volumeand economic benefits of E. grandis ×E. urophylla stand.