Once you have secured a Hong Kong employment visa, you are allowed to bring a spouse or family members of dependant age (below 18 years). Make an application for dependant visa for them to be allowed entry. You will be required to proof that the dependants are your family members (spouse and children) and can be able to support them at a standard that is above average while in Hong Kong.
The dependant visa allows your spouse to study and even seek gainful employment in Hong Kong. Notably, the dependant visa will only remain valid as far as the eligibility criterion is upheld.