what are the basic requirements when entering hongkong for visit?especially in hongkong immigration?

You have to hold a valid passport with at least 6 months remaining validity, I hear that Philippines immigration doesn't allow Filipino to exit the country if their passport doesn't have at least 6 months validity.

In fact, the Hk immigration just asks aliens to hold a passport with one month validity beyond the stay duration in Hong Kong, for example, you will stay in HK for one month, your passport has to have at least 2 months validity when you enter Hong Kong.

Besides the passport, you also need to hold a round-trip flight tickets which can prove your planned stay duration in Hong Kong. You are a philippines, for less than 14 days stay duration in Hk, a Hong Kong visit visa is not required, otherwise, you also need to obtain a Hk visit visa in advance.