只要是香港永久居民并且出身在中国就可以获得
不过香港永久居民得在香港住7年。。。

HKSAR passport - eligibility & application

You are eligible to apply for a HKSAR Passport if you are:
a Chinese citizen;
a permanent resident of the HKSAR; and
a holder of a valid Hong Kong permanent identity card.

For information on the eligibility and application for a HKSAR passport, pleaase visit the webiste at : http://www.gov.hk/en/residents/immigration/traveldoc/hksarpassport/index.htm

Chinese Nationality
You are regarded as a person of Chinese nationality if you are a Hong Kong resident:
(a) of Chinese descent who was born in Hong Kong or other parts of China; or
(b) who fulfils the criteria of Chinese nationality in the Nationality Law of the People's Republic of China.