〔Abstract〕 Objective To investigate associations of suicidal ideation with clinical features, inflammatory markers, and thyroid hormones in patients with schizophrenia. Methods The subjects of this study were 203 schizophrenic patients, grouped on the basis of suicidal ideation. Clinical characteristics were assessed using multiple scales. Neutrophil to lymphocyte ratio(NLR), platelet to lymphocyte ratio(PLR), monocyte to lymphocyte ratio(MLR) and thyroid hormones were also detected. SPSS 23.0 was used for statistical analyses. Results The prevalence of suicidal ideation was 21.7% in patients with schizophrenia. Logistic stepwise regression analyses showed that Calgary depression scale(CDSS) total score(OR=1.490, 95%CI=1.287-1.724,P<0.001), insomnia severity index scale(ISI) total score(OR=1.096, 95%CI=1.011-1.187,P=0.025), modified overt aggression scale(MOAS) total score(OR=1.111, 95%CI=1.016-1.215,P=0.021), MLR(Ln)(OR=15.123, 95%CI=3.868-59.125,P<0.001), and triiodothyronine(T3)(OR=0.037, 95%CI=0.003-0.388,P=0.006) were the independent influences of suicidal ideation. Additionally, receiver operating characteristic(ROC) curve analyses revealed that the five-item combination of CDSS total score, ISI total score, MOAS total score, MLR(Ln), and T3(AUC=0.908, 95%CI=0.867-0.949,P<0.001) had better ability to identify suicidal ideation. Conclusion The risk of suicidal ideation is relatively high in patients with schizophrenia, and there may be stronger associations between suicidal ideation and depression, insomnia, aggression, MLR, and T3.