can i stay if my h4 is denied and appeal is pending since 6 months?

The rule is that illegal presence does not accrue for individuals on F-1 status unless they have either received a denial from U.S.C.I.S. or an order from the immigration judge. In your case, you received a denial from U.S.C.I.S. on March 25, 2012, and appear to have have accrued illegal presence ever since. The exception would be if the H-4 denial acknowledged that you were still maintaining your F-1 status. Failing that, you should stay and wait for the results of your motion to reopen or reconsider (would not be an appeal since change of status applications are non-appealable) since you are already past the time that it would make any sense for you to leave the US. Having accrued illegal presence for over a year, you would be barred from returning to the country for 10 years if you now left. It also appears from your fact pattern that you have a fairly good chance of winning your motion.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 stay while your appeal is pending.  Here is an excerpt from Chapter 30.1(d) of the Adjudicator's Field Manual: (4) Requirements for Period of Stay Authorized by the Attorney General with Respect to Pending Change of Status and Extension Applications. (A) The application for change of status or for extension of stay was filed timely. To be considered timely, the application must have been filed before the previously authorized stay expired, as provided under 8 CFR 214.1(c)(4) and 8 CFR 248.1(b). (B) The alien did not work without authorization before the application for change of status or extension of stay was filed or while it was pending; and (C) The change of status or extension application has been pending with the Service for more than 120 days after the date the I-94 expired. (5) Effect of Decision on Unlawful Presence and Tolling. (A) Approved Applications. If the Service approves an E/S or C/S application, the alien will be granted a new period of stay authorized by the Attorney General, retroactive to the date the previously authorized stay expired, as applicable to the nonimmigrant classification under which the alien was admitted pursuant to 8 CFR 214.2. No unlawful presence accrues. This applies to aliens admitted until a specific date and aliens admitted D/S. (B) Denied applications. (i) Denial of Timely Filed Applications and Frivolous Applications; Unauthorized Employment. If the timely filed C/S or E/S application is denied because it was frivolous or because the alien engaged in unauthorized employment, any and all time after the Form I-94 expiration date will be considered unlawful presence, if the alien was admitted until a specific date. If, however, the alien was admitted D/S, unlawful presence begins accruing on the date of the Service's decision. (ii) Denial of Untimely Applications. If the application was untimely and was denied, unlawful presence begins accruing on the date the I-94 expired, regardless of the reason for denial. For aliens admitted D/S, unlawful presence begins accruing on the date of denial.