How do you catch entai in Pokemon soul silver?

Answer 1

Entei is a 'roaming' Pokémon, which means it is not in a fixed location, it actually changes what route it's on every time you do. Therefore, encountering it is merely based on luck. If you've encountered Entei already, an icon of its face should appear on your map, showing its current location. The only way to get into a battle with him is to keep switching routes until it comes to you.

Make sure you've got something that will keep it in the battle too, as it will otherwise flee the first chance it gets. You could use a Pokémon with the move Mean Look, or the ability Shadow Tag, for example.