Abstract: The distribution of pinitol in the masson pine seedlings and changes of pinitol content in needles of seedlings from different provenances under drought stress were studied. The results showed that: (1) The pinitol content in one year seedlings gradually increased along with the process of seedling growth and the peak of pinitol content appeared in the end of growing season. The pinitol content in twoyear seedlings was high at the beginning of growing season. But it was kept in a low level during the fastgrowing period. And the pinitol content increased again in the end of growing season. (2) The pinitol content in the stems was the highest (25.86 mg/g, DW), followed by needles (22.75 mg/g, DW) and it was the lowest in the roots (only 3.60 mg/g, DW). (3) The pinitol content in the needles of masson pine seedlings from different provenances increased along with the process of drought stress. The average pinitol content in the needles of seedlings from 5 provenances after 36 days severe drought stress was 41.38 mg/g, DW, 25.51% higher than control. It was 47.14 mg/g, DW after 54 days severe drought stress, 64.14% higher than control. The difference of pinitol content among different provenances was significant at the beginning of drought stress and it was not obvious after three cycles of severe drought stress.