I have student visa and currently doing my MBA. I am getting married to an US citizen at the end of Aug. Which form do I use to apply for green card?

If you are marrying a US citizen, you can adjust to permanent residence in this country if you are an F-1 student or J-1 student (assuming you are not subject to a two-year home residence requirement incurred by taking the J visa). You and your spouse would be filing forms I-130 relative petition and I- 485 adjustment of status to permanent residence application. Your husband would also have to fill out form I-864 affidavit of support and if he does not have the financial support power, you would need a co-sponsor with means to guarantee your financial support. Your paperwork would ultimately be filed to USCIS's lockbox in Chicago. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.

You can file all the forms needed at once.  Here is a link with more information: http://www.uscis.gov/portal/site/uscis/menuitem.eb1d4c2a3e5b9ac89243c6a7543f6d1a/?vgnextoid=9c8aa6c515083210VgnVCM100000082ca60aRCRD&vgnextchannel=9c8aa6c515083210VgnVCM100000082ca60aRCRD Once you file you won't need to worry about your student visa expiring since you will be pending adjustment (and that will be your new legal status).