Is roller coaster tycoon compadable with windows 7?

As standard, no.
However, you can make it compatible.
You can try downloading patches, or you could right-click on the .exe file, select 'Properties', then 'Compatibility' then try and make it playable on older versions of Windows. Ideally, you could try XP, as it works with pretty much everything now.

you can make it compatible and then play

Yes,surely.You can play such games for being compatible with Windows 7

Roller Coaster tycoon, or roller coter tycoon 2 , is not compatible with Windows 7. If you're talking about Roller Coaster Tycoon 3, yes it is.