Hi Pranav,
Goto YourName–>setup–>Customize–>home–>Home page components
Click New to create a custom components,
Give the Name to the components and then select HTML area
After that Select show HTML check box as shown in the screenshot
Then paste the following code,
<iframe src=”/00000000000?isdtp=lt” frameborder=”0″ height=”900″ width=”1280″></iframe>
Note:-/000000000 is the Id of the dashboard,change that into your dashboard Id which you want to display in the Home page.
Thanks