I can't catch ho-oh,iv watched the video but I still can't catch him. ..

Well using a masterball is probably the easiest way to go about doing it. If you have to resort to an Ultraball, then you're going to have a very hard time. That's really the only other Pokeball that will do any good, and it's still hard. Paralyze or sleep status on Ho-oh is probably the best way.

Well,first you have to have a rainbow wing and you get that from goldenrod city when you beat the team rocket grunts, the director comes in and gives you it and then you go to the tower (also you have to beat the leader)and theres a guy standing there if he stops you that means you don't have it if you do it will float up in the air then you do all the ladders(always going up).you will finnaly reach it.

First you need the rainbow wing(from goldenrod city beating the team rocket grunts)then you go the the tower and keep going up never down and soon you will reacch ho-oh and you might want to use a master ball but if you want to save it for like rayquaza or kyogre or any other legendary Pokemon oh and Lugia or lotios.

One way to get ho oh without having to use any master balls is either get one of your guys and get it to learn hypnosis and then get ho oh to red health and use hypnosis. After tha use an ultra ball and repededly tap a only and it should work make sure to save before you catch it.second you could get an action replay and go to bag codes and select 900 of every special pokeball and then youll get 900 master balls make sure you tap l and r at the same time and there you go.ps make sure your walking around before you tap l and r