 Hemay005 is a novel phosphodiesterase type 4PDE4 inhibitor being developed for the treatment of psoriasis. This study is the first administration of Hemay005 in humans to establish the initial safety, tolerability, and pharmacokinetic profile following single doses of Hemay005. A total of approximately 44 subjects will be randomized into 6 cohorts10mg, 20mg, 40mg, 80mg, 120mg, 180mg, approximately 8 healthy subjects will be enrolled 6 active and 2 placebo at each dose cohort by sentinel method1 active and 1 placebo,5 active and 1 placebo, with the exception of 10mg 4 active cohort. This study includes an 28-day Screening Period, a 1-day Treatment Period, and an End of Study Visit occurring approximately 11days 3 days after study drug administration. 