Embodiments of the present invention provide a method and an apparatus for determining a permission of an application program. The method for determining a permission of an application program in the present invention includes: receiving an installation request of a first application, where the installation request carries a first permission list that the first application applies for and a first shared user identifier requested by the first application; searching, according to the first shared user identifier, for at least one second application that uses the first shared user identifier and is already installed in a system; and if the first application is a plug-in of the second application already installed in the system, determining a permission of the first application according to the first permission list that the first application applies for and a permission in a second permission list corresponding to the first shared user identifier. The embodiments of the present invention make an application unable to add a permission of the application by adding a plug-in, lowering a risk of a system and improving security of the system.