http://www.ukba.homeoffice.gov.uk/si...s-visitors.pdf
If you plan to accommodate and support you sister during her visit, then you will need to provide a letter of invitation as well as financial documents.
You may also need to supplying evidence of your immigration status in the UK.
The main reason for a visit visa to be refused is they do not believe she will return to the Philippines. You need to supply lots of evidence to back this up.
