I kept one bottle of martini 10 years ago. But now it changed to dark rum color. Is it spoil?"?

Yes, it is spoiled. Ever see milk when it spoils, it all separates well that is what your bottle of martini has done. Stop being cheap and buy something new unless you are on a budget. You could always mix it with some cranberry juice and turn it into a sissy drink. You people and your dumb questions.