This paper aims to investigating the effects of fresh frozen plasma (FFP) on the release of nitric oxide (NO) in normal human lung microvascular endothelial cell. NO/Nitrite/Nitrate assay showed a much higher NO production in the conditioned media of FFP-treated human pulmonary microvascular endothelial cells (HPMECs). Phospho-kinase array and Western blotting revealed that FFP significantly increased the activation of AMPK 1, Akt1 and eNOS in HPMECs. Pretreatment with Compound C (AMPK inhibitor), LY294002 (PI3K/Akt inhibitor) or L-NAME (NOS inhibitor) inhibited AMPK 1/ Akt1/ eNOS cell signaling，FFP-induced eNOS activation and NO production in HPMECs. This study reveals a new mechanism in which FFP exerts its vasoprotective effect.