How to Beat Rayquaza on Pokemon Red

Level up your party until everyone is at least in the 30 to 35 range. Anything lower than that and Rayquaza will defeat your party members before they get a chance to do any serious damage.

Give at least five reviver seeds to each of the Pokemon in your party. With the reviver seed the Pokemon will automatically be restored with full health and power if it faints during battle. Once used, the reviver seed will turn into a plain seed.

Equip your Pokemon with a ranged item such as the "Silver Spike" which is thrown at the enemy to do damage from a distance. A minimum of 25 is required for these to be effective. Give Oran Berries to your Pokemon as well. Although these restore only 100 health points in battle they are cheaper than the reviver seeds.

Give two link boxes to your Pokemon so that they can link together their moves in battle. If you do not have these yet they are available from the shop in the game for 900 Poke. Bring along at least four sleep seeds as well to put Rayquaza to sleep.

Use ice moves like "Ice Beam" against Rayguaza as it is weak against these types of attacks. Throw the long-range items like the silver spikes at it to keep it at bay. Throw the sleep seeds at Rayquaza once it gets within range to do some easy damage while it is passed out. The oran berries your party members have will safeguard them from heavy attacks like Dragon Claw.

Perform linked moves on Rayquaza when it gets too close. Choose one attack from each Pokemon that will be linked together for bigger damage.