下载PHPExcel_1.8.0_doc.zip http://phpexcel.codeplex.com/，将解压后的文件夹里的Classes上传到网站的根目录下，Classes目录内的内容如下：

导出文件Excel.php

require_once dirname(__FILE__)."/Classes/PHPExcel.php";//引入PHPExcel
.....此处略去从数据库获取数据的过程，$a为需要导出的数组......
$numArr = array("A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","AA","AB","AC","AD","AE","AF","AG","AH","AI","AJ","AK","AL","AM","AN","AO","AP","AQ","AR","AS","AT","AU","AV","AW","AX","AY","AZ");
// Create new PHPExcel object
$objPHPExcel = new PHPExcel();

$arr = array("订单号","下单时间","城市","地区", "客户名称", "收货人", "联系电话", "收货地址", "ERP客户名称", "物流系统客户名称", "活动项目",
 "品牌", "型号", "颜色", "物流系统型号", "订货量", "单价", "代收货款", "红包", "价保返利", "运费", "实收金额", "付款方式", "订单来源",
 "上游厂商", "是否在仓", "快递面单号", "订单状态", "确认时间", "末次状态确认时间", "描述", "对应业务", "对应客服", "商家留言", "下单摘要",
 "业务员", "联系方式");
// 输出标题
echo date("H:i:s") , " Add some data" , EOL;
//设置换行
$objPHPExcel->getActiveSheet()->getStyle("H")->getAlignment()->setWrapText(true);
$objPHPExcel->getActiveSheet()->getStyle("Y")->getAlignment()->setWrapText(true);
//设置相应列的宽度
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension("A")->setWidth(15);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension("B")->setWidth(20);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension("G")->setWidth(15);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension("H")->setWidth(40);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension("I")->setWidth(15);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension("J")->setWidth(15);
//输出第一行
$objPHPExcel->setActiveSheetIndex(0)
   ->setCellValue("A1", $arr[0])
 ->setCellValue("B1", $arr[1])
 ->setCellValue("C1", $arr[2])
 ->setCellValue("D1", $arr[3])
 ->setCellValue("E1", $arr[4])
 ->setCellValue("F1", $arr[5])
 ->setCellValue("G1", $arr[6])
 ->setCellValue("H1", $arr[7])
 ->setCellValue("I1", $arr[8])
 ->setCellValue("J1", $arr[9])
   ->setCellValue("K1", $arr[10])
   ->setCellValue("L1", $arr[11]);


//输出内容
for($i=0;$i<count($a);$i++){
 $objPHPExcel->setActiveSheetIndex(0)
  ->setCellValue($numArr[0].($i+2), $a[$i]["order_sn"])
  ->setCellValue($numArr[1].($i+2), $a[$i]["add_time"])
  ->setCellValue($numArr[2].($i+2), $a[$i]["city"])
  ->setCellValue($numArr[3].($i+2), $a[$i]["region_name"])
  ->setCellValue($numArr[4].($i+2), $a[$i]["company"])
  ->setCellValue($numArr[5].($i+2), $a[$i]["consignee"])
  ->setCellValue($numArr[6].($i+2), $a[$i]["mobile"])
  ->setCellValue($numArr[7].($i+2), $a[$i]["address"])
  ->setCellValue($numArr[8].($i+2), "")
  ->setCellValue($numArr[9].($i+2), "")
  ->setCellValue($numArr[10].($i+2), "")
  ->setCellValue($numArr[11].($i+2), $a[$i]["brand_name"]);
}

// Rename worksheet
echo date("H:i:s") , " Rename worksheet" , EOL;
$dirName = date("Ymd");//目录名
$fileName = date("YmdHis");//文件名
$objPHPExcel->getActiveSheet()->setTitle($fileName);


// Set active sheet index to the first sheet, so Excel opens this as the first sheet
$objPHPExcel->setActiveSheetIndex(0);


// Save Excel 2007 file
echo date("H:i:s") , " Write to Excel2007 format" , EOL;
$callStartTime = microtime(true);
if(!opendir("../excel/".$dirName)){
 mkdir("../excel/".$dirName);
}
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, "Excel2007");
$objWriter->save("../excel/".$dirName."/".$fileName.".xlsx");

$end = getCurrentTime();
$spend = $end-$begin;
if ($spend > 30){
 echo "<script>if(confirm("执行超时！")){ window.history.back(-1);}</script>";
 exit;
}
header("Location:http://".$_SERVER["HTTP_HOST"]."/excel/".$dirName."/".$fileName.".xlsx");