I want to use the Angel race. It is for D&D 3.5, can I use it on Pathfinder? If not, what do I need to change to make it compatible?
Yes and no.
In general, custom races made for D&D 3.5 will work just fine in Pathfinder. Nothing really major changed as far as races are concerned between 3.5 and Pathfinder. The biggest thing to look out for is that Pathfinder no longer has the concept of level adjustment, so there typically needs to be some houserules to allow more powerful races, if they'd have an LA. You also want to make sure that any races with an LA of 0 have a total of +2 to ability scores, rather than +0.
My previous DM had a houserule that worked pretty well for this. We used point buy for stats, and he ruled that for each +1 LA, you lost 4 points from your point buy total. Since we only had fairly small LAs, this worked pretty well.
That said, the race that you linked is pretty powerful. It has extremely favorable stats, flight, DR, a suite of resistances, smite, SR, change shape, and a couple other powers. I'd give that race an LA of +4, at least. I would not suggest using that race in a Pathfinder game, unless everyone is playing a similarly powerful race, and you're comfortable with a high-power game.
Your question isn't really about 3.5 races in general - you should ask about the actual problem you have. Your problem is that you want to play an angel in Pathfinder and want to know how. Rather than use a super overpowered homebrew 3.5 race, you have a couple options.