Objective To evaluate CT scanning value in the diagnosis of pulmonary lymphangioleiomyomatosis(PLAM).Methods CTfindings of PLAM proved pathologically in 13 cases were retrospectively analyzed including distribution,morphosis and complication oflesions.Results 3 were lobar or segmental lesion and 10 were desseminated lesion.The fine nodules and pulmonary cystic space were showed on conventional CT scanner.The fine nodules(1~2 mm in diameter)and pulmonary cyst spaces(1 ~4 mm walled )were seen on high resolution CT.The most of cystic spaces were round.13 cases of pathologic species were retrospectively reviewed.The results showed that 12 cases were PLAM and 1 case was pulmonary tuberous sclerosis.Conclusion In young female, the fine nodules or pulmonary cyst spaces were presented on CT scan,PLAM should been strongly suspected.