Abstract: This paper reported the physico mechanical properties of immature Pinus yunnanensis Franch grown in Kunming compared with the physico mechanical properties of mature Pinus yunnanensis.According to test results.Most of physico mechnical properties of immature Pinus yunnanensis had reduction compared with mature Pinus yunnanensis, while its compression parallel to grain, the bending strength and the modulus of elasticity to grain which were main properties of wood had little differences in physico mechnical properties.Since the toughness and hardness of the timber showed little difference between the two kinds of timber, full use of the timber from intermediate cutting operation of immature Pinus yunnanensis could be made as well.