NSString *dateStr = @"1970-01-01 00:00:00 +0000";

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

formatter.dateFormat = @"YYYY-MM-dd HH:mm:ss zzz";

NSDate *date = [formatter dateFromString:dateStr];


备注:如果带时区的一定要加上 zzz