1、后台System=>Web=>Url Options下的Add Store Code to Urls属性值选为Yes;

2、修改app/code/core/Mage/Core/Model/Store.php文件下的getStoreInUrl函数，把

public function getStoreInUrl()
    {
        return Mage::isInstalled() && $this->getConfig(self::XML_PATH_STORE_IN_URL);
    }

public function getStoreInUrl()
    {
    	if($this->getCode() == 'test1' || $this->getCode() == 'admin'){
        	return Mage::isInstalled() && $this->getConfig(self::XML_PATH_STORE_IN_URL);
    	}else{
    		return false;
    	}
    }

3、修改app/code/core/Mage/Core/Controller/Request/Http.php下的setPathInfo函数，把

if ($this->_canBeStoreCodeInUrl()) {
                $pathParts = explode('/', ltrim($pathInfo, '/'), 2);
                $storeCode = $pathParts[0];

                if (!$this->isDirectAccessFrontendName($storeCode)) {
                    $stores = Mage::app()->getStores(true, true);
                    if ($storeCode!=='' && isset($stores[$storeCode])) {
                        Mage::app()->setCurrentStore($storeCode);
                        $pathInfo = '/'.(isset($pathParts[1]) ? $pathParts[1] : '');
                    }
                    elseif ($storeCode !== '') {
                        $this->setActionName('noRoute');
                    }
                }
            }

if ($this->_canBeStoreCodeInUrl()) {
                $pathParts = explode('/', ltrim($pathInfo, '/'), 2);
                $storeCode = $pathParts[0];
		if($storeCode == 'test1' || $storeCode == 'admin'){
	                if (!$this->isDirectAccessFrontendName($storeCode)) {
	                    $stores = Mage::app()->getStores(true, true);
	                    if ($storeCode!=='' && isset($stores[$storeCode])) {
	                        Mage::app()->setCurrentStore($storeCode);
	                        $pathInfo = '/'.(isset($pathParts[1]) ? $pathParts[1] : '');
	                    }
	                    elseif ($storeCode !== '') {
	                        $this->setActionName('noRoute');
	                    }
	                }
		}
            }

'test1'为要要添加code的子站点