procedure TMAINFORM.TCPServer1ClientRead(Sender: TObject;
  Socket: TCustomWinSocket);
var
  iLength,I，iStart, iRevCount: Integer;
  iReceived: Integer;
  buff: array of byte;
  S:STRING;
begin
   S:='';
   iStart := 0;
   iLength:= Socket.ReceiveLength;
   iRevCount := iLength; //这里加入的
    SetLength(buff, iLength);
    MEMO1.Lines.Add(INTTOSTR(ILENGTH));
   while iLength>0 do
   begin
     iReceived := Socket.ReceiveBuf(buff[iStart], iLength); //这里修改了注意
      iStart := iStart + iReceived ; //这里加入的
     iLength := iLength - iStart;
   end;
   //下面你的iLength 使用 iRevCount 替换了
   FOR I:=0 TO iRevCount -1 DO
     BEGIN
       S:=S+INTTOSTR(BUFF[I]);
     END;
   MEMO1.Lines.Add(S);
   buff:= nil;
end;