 Randomization Blocked randomization was adopted and the intensive and conventional blood pressure control treatments were allocated at random in a ratio of 1:1 in blocks of sizes of 4,6,8, and 10 to 360 subjects. The study is an open label trial. After investigators in each participating centers screened the potential patients within 4 hours after acute onset, a number from a pre-allocated envelope will be gotten and which denotes which group the patient will be allocated to. 