How to change exposed filter select box style in views i have on exposed filter in views.it in defatult drupal select box style. how to change it like attached screenshot.
You can use fancyselect module.

Fancy select is a jQuery plug-in developed by Octopus Creative.
This module loads fancySelect jQuery plug-in, which converts simple HTML select DOM elements with a specified CSS class into a stylish select box. You may configure DOM CSS from settings form.