What is the most powerful Pokemon move?

Answer 1

The most powerful attack you can make:

Have a Shuckle with max Defenses use Defense Curl, then Power Trick, and then Rollout. The fifth turn of rollout would be the strongest move ever. If stat boosters and items are used, it can be even more powerful.

However, the attack with the most base power is Explosion, with 250 base power and 100 accuracy.

Here:

Rock Wrecker

Rock, 150 Power, 90 Accuracy (only Rhyperior can learn this)

Giga Impact

Normal, Power 150, Accuracy 90

Hyper Beam - Buy TM in Veilstone Department Store

Normal, Power 150, Accuracy 90

Draco Meteorite - Grandma can teach a Dragon Type this move if it loves you ( on the path to Celestic town)

Dragon, Power 140, Accuracy 90

Roar of Time(Dialga knows this Diamond and Platinum)

Dragon, Power 150, Accuracy 90 (Basically Dragon Hyper Beam)

Special Rend (Palkia knows this move in platinum and Pearl)

100 Power, 95 accuracy, increased critical hit rate

Shadow Force ( Only Giratina in Platinum knows this)

Ghost, Power 120, two turn attack, Accuracy 100

The lesser ones are

Fire Blast (Buy TM in Veilstone)

Fire, Power 120, Accuracy 80

Focus Blast (Buy TM in Veilstone)

Fighting, Power 120, Accuracy 70

Thunder (Buy TM in Veilstone)

Electric, Power 120, Accuracy 70 ( Electrical Focus Blast)

Answer 2

As of Pokémon X and Pokémon Y, Self-Destruct and Explosion are the two most powerful moves in Pokémon with a base power of 250 for Explosion and 200 for Self-Destruct however V-create is the next most powerful move with a base pwoer of 180 and then there are moves such as Hyper Beam, Focus Punch, Hydro Cannon, Blast Burn, Frenzy Plant, Rock Wrecker, Giga Impact, Roar of Time and Head Smash that are all tied with the base power of 150.