I am single but have 2 dependants ,can I claim head of household?

there are many other rules besides having dependents please read the following

1) was the dependent claimable solely because of a multiple support agreement - if yes you cannot file as HOH, if no was the dependent legally related to the taxpayer by blood - if no you cannot file as HOH.
2) Do you qualify as a surviving spouse because your spouse died in the preceding 2 years and you maintain a home for a child whom you are able to claim as a dependent whether you do or not - you cannot file as HOH but as surviving spouse.
3) Were you a nonresident alien at any time during the year - if yes you cannot file as HOH.
4. was the dependent a married child of the taxpayer? if yes, will the dependent child file a joint return with their spouse? if yes you cannot file as HOH. If the dependent child was not married or if married will not file a joint return with their spouse then did the legally related dependent use the taxpayer’s household, for which the taxpayer paid at least ½ the cost, as their principal place of abode for more than ½ the year – then you can file as HOH.