Objective To establish the diagnosis of am niotic fluid em bolismwith blood sam ples by liq-uid-based cytology technique and to study the validity of m ethod. Methods The blood sam ples were collected from patients who suffered from am niotic fluid em bolism. The com ponents of am niotic fluid in blood samples were examined with blood smear by two direct smear methods(supernatant smear, sedi-ment smear) and two liquid-based cytology methods(autom atic smear, manual smear). The positive de-tection rate of each m ethod was calculated. Results The positive detection rates of two liquid-based cy-tology methods(84.6% and 92.3%, respectively) were m uch higher than those of two direct methods(53.8% and 61.5%, respectively). Conclusion The liquid-based cytology technique could im prove the positive detection rate of am niotic fluid em bolism.