installation - Importing ArcPy in PyCharm?

>>> import arcpy
Traceback (most recent call last):
  File "", line 1, in 
  File "D:\Program Files (x86)\ArcGIS10.5\Desktop10.5\ArcPy\arcpy\__init__.py", line 22, in 
    from arcpy.geoprocessing import gp
  File "D:\Program Files (x86)\ArcGIS10.5\Desktop10.5\ArcPy\arcpy\geoprocessing\__init__.py", line 14, in 
    from _base import *
  File "D:\Program Files (x86)\ArcGIS10.5\Desktop10.5\ArcPy\arcpy\geoprocessing\_base.py", line 14, in 

    import arcgisscripting
ImportError: DLL load failed: The specified module could not be found.

What does it mean?

By the way,I have downloaded python 3.7 for studying, which means I may have two python interpreter in my system.

Is it the reason I can't import arcpy?