As title,how can I cancel(or dispell?) Cleric spell Sanctuary?True Sight?
Is there other thing? Maybe Detect Illusion? But is that all?...

A successful dispel magic should do the trick. I can't think of any other spells that would work right off the bat.

It's not an illusion per say, so if True Sight or any other illusion-dispelling magic works, then it wouldn't make sense if you'd ask me :p

Ach so! It´s not illusion?
My Keldorn´s True Sight always works very well with a near death cleric who then casts Sanctuary...but what should I do if I don´t have Keldorn in the party??? After all, True Sight is a sixth level spell and I won´t get it so soon after Irenicus dungeon ne...

True Sight and Oracle spells successfully dispel Sanctuary. Although, Sanctuary is a spell of aburation school, it is also an Illusionaryprotection spell. Its description also suggests this.

There is no contradiction between being an abjuration spell and being an Illusionaryprotection spell. (The former is the spell's school, while the latter is its secondary effect and determined in the spell's 'secondary type' flag in the spell's file.)

Really? Hrrmm.. I always pictured the Sanctuary spell being an impenetratable barrier, granted by the god in question. Not an illusionary protection.

Well, dispellable by True Sight still doesn't make sense in my eyes!

Why? True sight is just a better sight granted by your God.

How come Arcane classes can cast it aswell then? And why should seeing better help you bash your head through a wall?

You said it yourself, it's just better sight :p

It's not an illusion it just makes whomsoever uses it to become invulnerable ...

It is not a 'magical coccon from the god which grants invulnerability'. (although it is cool to tink like that) Sanctuaried creatures are still vulnerable to area effect spells. Sanctuary just causes enemies not being able to see and target the priest. It is more like a cheap invisibilty spell which can only be casted on yourself. Any method to dispel illusions/invisibility will get rid of it. Also, IIRC, those enemies who can naturally see invisible targets ignore the meager protection of Sanctuary too.

Sanctuary is best described as "turning away eyes". It doesn't make you invisible, or invulnerable. It just...encourages people and things not to look at or notice you.