Question

The rime of the ancient mariner real book... Why did he killed the albatross

Answer 1

Sailors have always been superstitious about omens and I believe the Mariner was no different.  At first the bird was hailed as a good luck charm because the winds started blowing after the albatross appeared, but when the bird spoke to the Mariner as a friend, he killed it immediately after:
It turns out in the end that killing the albatross is probably the reason that the Mariner survives all the cursed things that end up killing his entire crew.  While most people are familiar with the metaphor of 'carrying an albatross' around one's neck as a representation of some psychic burden, Coleridge also seems to imply that this curse may also be a blessing in disguise.  Our trials and tribulations often are.

Answer 2

The mariner shot the albatross because he believed that it was an unlucky omen and the source of their diminished wind. He believed that, once the albatross was dead, the wind would return, and they would be able to cross the ocean at a much greater speed. Instead, after he shot the albatross, the wind failed altogether. They were stranded in the middle of the ocean as punishment for his actions. He killed an innocent creature, and as consequence, he was forced to watch his crew die of thirst and starvation. He hung the dead bird around his neck as a symbol of his shame. Only once he repented on his actions, did the wind return. The spirits of his crew helped to guide the ship, but they did not return to life. The message of this story is that actions have permanent consequences, even when you try to make amends.