In article submission , If i use two keyword A then B but my url is same for both keywords. Please let me which is most preferred keyword for Google.
Google will give equal preference to both urls, but its better that you hyperlink different keywords with different links.
If you taking about Google then It depend upon the popularity of both the keywords and their Competition. Google will not decide only on the basis of one article.
Relevancy is key. Make sure the keywords are relevant to the content on the page the url points to. If submitting to a blog, try to make sure it is related to your site's topic, or if submitting to an article directory, ensure you submit to the category that matches your site's topic most accurately. Try not to overlap single keywords between the two key phrases (assuming you are using 2-4 keyword phrases).