During May 2015 to October 2016, this prospective study enrolled a total of 438 patients with acute ischemic stroke(AIS), meanwhile, records regarding the severity of initial stroke and neurological outcomes at three months, as well as other examination were completed in patients on admission, as well as the measurement and evaluation of fasting blood glucose(FBG) levels. At admission, the median FBG levels in patients with a minor stroke (n=124), [P<0.001]) was significantly lower than that observed in patients with other degrees of stroke. The poor functional outcome distribution across the FBG quartiles ranged from 13.8 % (first quartile) to 59.6% (fourth quartile), with P <0.001. Compared with the reference category (first quartile), patients in the highest quartile had a relative risk of 3.12 (95% confidence interval [CI], 1.88-6.15; P<0.001) while those in the second and third quartiles had relative risks of 1.76 (95% CI, 1.21-3.03; P=0.035) and 2.23 (95% CI, 1.50-3.69; P=0.010), respectively. Furthermore, in the patients without diabetes, FBG level was observed to be increased and indicated an increased risk of disability (odds ratio [OR]: 1.30 (95%CI 1.13-1.61), P=0.002), however, similar result was not detected in patients with prior diabetes (P=0.089). In conclusion, elevated FBG levels after stroke may suggest poor functional outcome at 3-month in patients without a previous history of diabetes.