i have a unit 4 might in base, i use alpha strike in the battlefield there is an akali with 4 might also, but it is in the battlefield fortified position and has wuju Wuju Bladesman, Starter legend

It depends — the Wuju Bladesman +2 and Fortified Position's Shield 2 both only exist while Akali is a defender in a Combat Showdown, so whether she survives hinges on whether combat is actually underway when Alpha Strike resolves.

If it is — you're attacking Fortified Position, so Akali is the Defender — she's 4 base + 2 Shield + 2 from Yi = 8 Might, and your 4 damage isn't close to lethal. If instead you're just in your Main Phase with no combat running, neither bonus is active: Shield and the "defends alone" bonus are defender-only passives, so she's a plain 4-Might unit and 4 damage kills her (FAQ #7096). Note Alpha Strike's damage is fixed when it resolves, so it's your unit's Might at that moment — 4.

One wrinkle: if this is Akali, Silent (the 4-Might Calm one), her passive also makes her unchoosable by enemy spells and abilities unless she's in combat, so outside combat Alpha Strike couldn't even legally target her. And whichever side owns Wuju Bladesman, its +2 never pumps your Alpha-Striking unit — it only applies to a friendly unit defending alone, and yours is sitting at base.