is there any one implemented auto failover with 2 bgp peer. would you share with me. if 1 bgp peer down so the network will advertise to other bgp peer automaticly.

That is not the way BGP is supposed to work. You should always advertise your network to both peers (and learn routes from both), and if you want to prefer one peer over do other when both are online then you can play tricks with AS PATH length, local preference and MED.
There is no active/standy concept as such in BGP.

--Tom

You can try to advertise different subnet size to each peer.

For example (your IP are 10.0.0.0 - 10.0.1.255 or /23):

Peer A for 10.0.0.0/24
Peer B for 10.0.0.1/24

You can advertise to :

Peer A:
- 10.0.0.0/24
- 10.0.0.0/23

Peer B:
- 10.0.0.1/24
- 10.0.0.0/23

So if you have peer problem with Peer A, 10.0.0.0/24 still work through the other peer, as it's also advertise as 10.0.0.0/23 and vice versa.