Hi ShuangLiu,
Yes, it is recommended to uninstall the previously version of Office and then re-install the latest Office from Office 365 portal.
Please refer this article to uninstall Office 2013: https://support.office.com/en-us/article/Uninstall-Office-2013-or-Office-365-from-a-Windows-computer-9dd49b83-264a-477a-8fcc-2fdf5dbf61d8?ui=en-US&rs=en-US&ad=US
Please refer this article to Install Office using Office 365 for business: https://support.office.microsoft.com/en-us/article/Install-Office-using-Office-365-for-business-72977511-dfd1-4d8b-856f-405cfb76839c?CorrelationId=eda13c46-8ee7-4221-850c-dedd673aefc6&ui=en-US&rs=en-001&ad=AL
Thanks,
Mills Fan