Navigate to File | Project StructureCtrl+Shift+Alt+S.
In the Project Structure dialog, select SDKs under the Platform Settings section, click , and from the popup menu, choose Python SDK.
In the left-hand pane of the Add Python Interpreter dialog, select System Interpreter.
In the Interpreter field, type the fully-qualified path to the required interpreter executable, or click and in the Select Python Interpreter dialog that opens, choose the desired Python executable and click OK.
If IntelliJ IDEA detects no Python on your machine, it provides two options: to download the latest Python versions from python.org or to specify a path to the Python executable (in case of non-standard installation).
You will need admin privileges to install, remove, and upgrade packages for the system interpreter. When attempting to install an interpreter package through an intention action, you might receive the following error message: As prompted, consider using a virtual environment for your project.
Click OK to complete the task.
For any of the configured Python interpreters, you can:
, and from the popup menu, choose Python SDK. 
and in the Select Python Interpreter dialog that opens, choose the desired Python executable and click OK.
