i don't have seed i just download the wallet from electrum.org and start using it i just enter a password ! please help me what to do ?
It sounds like you have used Electrum in the past and created a 2FA wallet previously. When you reinstalled Electrum, it would have found the old wallet (uninstalling Electrum doesn't remove the data directory containing wallets) and used that old wallet by default without asking you to generate a new one.
In any case, as Abdussamad has already said, without the seed or the Google Authenticator "secret" for this wallet, your coins are lost.