Where can I get registration form of SSI? I have proprietorship firm.

Small Scale and ancillary units (i.e. undertaking with investment in plant and machinery of less than Rs. 1 Cr) should seek registration with the Director of Industries of the concerned State Government.

Registering your SSI Unit:

The main purpose of Registration is to maintain statistics and maintain a roll of such units for the purposes of providing incentives and support services.

States have generally adopted the uniform registration procedures as per the guidelines. However, there may be some modifications done by States. It must be noted that small industries is basically a state subject. States use the same registration scheme for implementing their own policies. It is possible that some states may have a 'SIDO registration scheme' and a 'State registration scheme'.

You can get further details on the registration along with the required forms / formalities at http://www.dcmsme.gov.in/howtosetup/grgxx01x.htm