uses UrlMon, WinInet;

{-------------------------------------------------------------------------------

  过程名:    SetProcessProxy

  作者:      kelei

  日期:      2013.08.03

  参数:      aProxyServer代理服务器; aProxyPort代理服务器端口

  返回值:    True设置成功

  SetProcessProxy('127.0.0.1', 80);

-------------------------------------------------------------------------------}

function SetProcessProxy(const aProxyServer: string; const aProxyPort: Integer): Boolean;

var

  vProxyInfo: TInternetProxyInfo;

begin

  vProxyInfo.dwAccessType := INTERNET_OPEN_TYPE_PROXY;

  vProxyInfo.lpszProxy := PChar(Format('http=%s:%d', [aProxyServer, aProxyPort]));

  vProxyInfo.lpszProxyBypass := PChar('');

  Result := UrlMkSetSessionOption(INTERNET_OPTION_PROXY, @vProxyInfo, SizeOf(vProxyInfo, 0) = S_OK;

end;

{-------------------------------------------------------------------------------

  过程名:    SetProcessUserAgent

  作者:      kelei

  日期:      2013.08.03

  参数:      aUserAgent HTTP请求头UserAgent内容

  返回值:    True设置成功

  SetProcessUserAgent('Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A334 Safari/7534.48.3')

-------------------------------------------------------------------------------}

function SetProcessUserAgent(const aUserAgent: string): Boolean;

begin

  Result := UrlMkSetSessionOption(URLMON_OPTION_USERAGENT, PChar(aUserAgent), Length(aUserAgent), 0) = S_OK;

end;

另一个办法：http://delphitop.com/html/xitong/2995.html