Objective To observe the changing characteristics of plasma lysophosphatidic acid (LPA) or acidia phospholipid (AP) levels in patients with obstructive sleep apnea syndrome-associated(OSAS)acute cerebral infarction and to explore the pathophysiological mechanisms of OSAS-related stroke so as to provide basis for clinical antithrombotic therapy. Methods Thirty-six patients of OSAS, 32 patients of OSAS-related acute stoke and 36 patients of acute stoke without OSAS diagnosed by clinical and accessory examinations were enrolled in the current study. Thirty-eight age-matched healthy subjects were recruited as controls. The changes of the plasma LPA and AP levels were measured. Results Within 24 hours after symptom onset, the plasma LPA and AP levels in the OSAS-related acute cerebral infarction group (LPA(3. 78 ±0. 56) μmol/L; AP(7. 63 ± 1. 38) μmol/L) were significantly higher than those in the OSAS group(LPA(3. 17 ±0. 65) μmol/L; AP(6. 60 ± 1. 20) μmol/L) ,the not OSAS-related acute cerebral infarction group (LPA (3. 40 ± 0. 59)μmol/L; AP (6. 41 ± 1. 37)μmol/L) and the control group (LPA(2.76±0.45)μmol/L;AP(4.52±0. 83) μmol/L (P < 0. 01)) . The levels of LPA and AP in the OSAS group and the not OSAS-related acute cerebral infarction group were significantly higher than those in the control group(P<0. 01). Seven days after symptom onset, the plasma LPA and AP levels in the OSAS-associated acute cerebral infarction group (LPA(3.08 ± 0. 58) μmol/L; AP(6. 15 ±1. 14)μmol/L) were still higher(P < 0. 01) . The plasma LPA levels were not significantly different among the OSAS-related acute cerebral infarction group, the not OSAS-related acute cerebral infarction group and the control group 21 days after symptom onset, whereas the plasma AP levels in the OSAS-related acute cerebral infarction group (5. 04 ± 0. 83) μmol/L were still significantly higher than those in the not OSAS-related acute cerebral infarction group (4. 57 ± 0. 94) μmol/L and the control group (P < 0.05). Conclusions The significantly elevated plasma LPA and AP levels in patients with OSAS suggested that platelets in vivo are in an activated state and in cerebral ischemia and hypoxia state, especially for the OSAS-related acute cerebral infarction patients. The activated state of platelet may persist for a long time, thus the time window for antithrombotic therapy may be longer.