Pioglitzone, an oral anti-diabetic drug which can reduce insulin resistance and decrease inflammation. It has been proven to be an effective neuroprotective agent in animal model of ischemic stroke. In this study, the investigators will conduct a phase II clinical trial (double-blind, randomized placebo controlled study) to survey the neuroprotection effect of pioglitazone in stroke patients with hyperglycemia. A total of 152 acute ischemic stroke patients with hyperglycemic will receive insulin or sulfonyurea for blood sugar control, and will be randomly randomized into intervention (Pioglitazone 30mg once a day p.o,) and control group (placebo). The investigators expect to prove the neuroprotective efficacy of Pioglitazone in acute stroke with hyperglycemia and identify the biomarkers associated with good neurological outcome in patients with Pioglitazone treatment from the investigators clinical trial.