In this paper, physical and mechanical properties of Pinus elliottii with different thinning intensities and planting densities were studied. The results show that the radial variances of annual ring width, percentage of late wood and basic density with different thinning intensities are almost the same. The effect of thinning intensity on annual ring width and mechanical properties is significant, while that on percentage of late wood and shrinkage is not significant. 45% thinning intensity can not only accelerate the growth of Pinus elliottii significantly, but also improve the mechanical properties, and have no significant effects on density and shrinkage. The effect of planting density on volume, total shrinkage and mechanical properties is significant, while that on air density is not significant. Pinus elliottii with 3.5 m×3.5 m planting density not only grow rapid, but also have relatively high mechanical properties.