把文件读入Tstrings在pos找到你要找的字符串不就可以了?
var
Strl:Tstrings
I:integer;
substr:string;
begin
strl:=Tstringlist.create;
strl.loadfromfile('c:\xxxx.html');
for I:=0 to strl.count-1 do
begin
substr:=strl.string[i];
if pos('你要找的字符串',substr)>0 then
breark;
edn;
showmessage(substr);
end;