尝试 dateWithTimeInterval：SinceDate：

NSMutableArray dates = [NSMutableArray array];
NSDate *curDate = startDate;
while([curDate timeIntervalSince1970] <= [endDate timeIntervalSince1970]) //you can also use the earlier-method
{
    [dates addObject:curDate];
    curDate = [MSDate dateWithTimeInterval:86400 sinceDate:curDate]; 86400 = 60*60*24
}
//here maybe an additional check if the enddate has to be inserted or not