【Objective】 To investigate the effects and mechanisms of different doses of fingolimod (FTY720) on non-antibody-mediated transfusion-related acute lung injury (TRALI). 【Methods】 A TRALImouse model was constructed using lipopolysaccharide (LPS) pre-stimulation and platelets (Plt) of different storage days for second strike. The success of the modeling was determined by protein concentration in lungtissue homogenates, myeloperoxidase (MPo) activity, lung wet/dry weight ratio (W/D ratio), lungtissue damage score and pathological sections. Ceramide and sphingosine-1-phosphate (S1P) contents in platelets of different storage days were detected. FTY720 was administered 1 h after LPS injection to investigate the role of FTY720 in TRALI. The expression levels of vascular endothelial cadherin (VE-cadherin) and zonula occludens-1 (ZO-1) were analyzed by WB. 【Results】 Mice infused with stored 5-day Plt (d5Plt group) exhibited typical signs of TRALI, and the differences in lungtissue homogenate protein concentration (6 546.38±409.50) μg/mL, MPO activity (49.38±4.43) U/L, W/D ratio 4.79±0.21, and lungtissue damage score 7.24±0.38 from the rest of the groups were statistically significant (P<0.05). With the increase of platelet storage time, the ceramide content gradually increased and S1P content gradually decreased, and the ratio of the two was imbalanced. d5Plt showed statistically significant differences (P<0.01) in ceramide content (58.37±5.69) μmol/L and S1P content (149.81±4.86) nmol/L from the rest of the groups. After preventive administration of FTY720, 1 mg/kg FTY720 had no significant effect on TRALImice, whose lungtissue homogenate protein concentration (6 170.26±545.50) μg/mL, MPO activity (45.97±4.79) U/L, W/D ratio 4.88±0.25, and lungtissue damage score 7.92±0.65 were significantly higher than those of the normal and LPS control groups (P<0.01). The low-dose (0.5, 0.2, and 0.1 mg/kg) FTY720 group alleviated lung injury, and its protein concentration, MPO activity, W/D ratio, and lungtissueinjury score were significantly lower than those of the d5Plt group (P<0.05). Pathological sections also showed similar results. In terms of endothelial intercellular junctionprotein expression, the VE-cadherin expression levels in the 1 mg/kg FTY720 group were significantly lower than those in the normal and LPS control groups (P<0.05), and the VE-cadherin and ZO-1 expression levels in the low-dose (0.5, 0.2, and 0.1 mg/kg) FTY720 group were significantly higher than those in the d5Plt group (P<0.05), which tended to be normalized. 【Conclusion】 In this study, a TRALImouse model was successfully established by one strike of LPS and two strikes of d5Plt. Low doses of FTY720 (0.5, 0.2, 0.1 mg/kg) were protective against TRALI, while high doses of FTY720 (1 mg/kg) may aggravate the symptoms of TRALI. This protective effect may be somewhat dependent on the expression of VE-cadherin and ZO-1.