I read following link to install and configure composer:
Composer
when I run command "composer install" then required dependencies are downloading on home directory while I need these to be downloaded on my project /vendor directory .
I have move composer.phar to my project root but it still can’t work.
You have to place composer.phar in your project directory (the same directory where composer.json is) and if you run the command it also has to be in that exact directory. So before running composer, change the directory to your project dir.
If you are following the guide you linked, why do you have a composer.phar in you home dir? the blog clearly suggests moving it to /usr/local/bin so that it is globally available.