Hello Friend, I am doing seo for my client's site so he wants to ranked in google.ca so i should submit directory in .com or ca directory.
Don't submit to either! Let Google find the site naturally. The site will be indexed on Google .com and Google.ca whether you like it or not but you can ensure higher rankings on the .ca site by making sure Google KNOWS that the site is Canadian. Make sure you host the site on a Canadian server with a Canadian IP. Make sure the site has a .ca TLD. Make sure that the full, word CANADA is include in all addresses. etc
Make sure you specify that the site is located in canada within the google webmaster tools. This is very important for rankings in the .ca google search engine.