Objective To investigate the effect of onset-to-needle time(ONT)on early neurological deterioration(END)in patients with acute ischemic stroke(AIS).Methods From June 2020 to June 2023,AIS patients receiving intravenous thrombolysis treatment in the Neurology Department of Seventh People's Hospital of Zhengzhou were continuously enrolled.Patients were divided into the END group(n=96)and non-END group(n=293)based on whether their NIHSS score increased by ≥4 points compared to baseline after 24 h.Baseline and clinical data of the two groups were collected,and relevant influencing factors were analyzed through univariate analysis,multivariate analysis,and subgroup analysis.A logistic regression model predicting the occurrence of END in acute stroke patients was constructed,and the model's predictive ability was evaluated by ROC curves.Results The results of the univariate analysis showed that there were statistically significant differences in age,total cholesterol,low-density lipoprotein cholesterol(LDL-C),lipoprotein-associated phospholipase A2(Lp-PLA2),white blood cell count,activated partial thromboplastin time(APTT),and ONT between the END group and non-END group(all P＜0.05).Additionally,there were statistically significant differences in the distribution of cardiac history,infarct location,and TOAST classification between the two groups(all P＜0.05).The results of the multivariable logistic analysis showed that age(OR=1.095,95％CI:1.029-1.165,P=0.004),LDL-C(OR=2.779,95％CI:1.355-5.694,P=0.005),Lp-PLA2(OR=1.007,95％CI:1.001-1.014,P=0.047),complete anterior circulation infarction(compared to lacunar infarction as control,OR=8.045,95％CI:5.175-12.503,P=0.024),cardioembolic stroke(compared to small vessel occlusion patients as control,OR=12.794,95％CI:8.411-19.462,P=0.002),and ONT(OR=1.014,95％CI:1.001-1.026,P=0.029)were independent risk factors for END in patients with AIS.Subgroup analysis based on the NIHSS score at admission showed that for moderate and severe subgroups,each additional minute of ONT increased the risk of END by 1.4％(95％CI:1.001-1.027,P=0.032)and 2.9％(95％CI:1.008-1.050,P=0.006),respectively.A predictive model was established based on the Logistic analysis results,and a nomogram predicting the risk of END outcome was created.The area under the ROC curve was calculated to be 0.922(95％CI:0.859-0.984,P＜0.001),indicating good predictive performance.Conclusions In clinical practice,patients with high-risk factors such as age,LDL-C,Lp-PLA2,TOAST classification,and infarct location should be given more attention.Timely thrombolytic therapy should be initiated,and patients'families should promptly seek medical assistance.Additionally,optimizing the diagnostic and treatment process,reducing ONT,and minimizing the occurrence of END in patients are crucial.