1.去官網下載deb包，例如包名：

virtualbox-5.2_5.2.18-124319_Debian_stretch_amd64.deb

2.安裝

sudo dpkg -i virtualbox-5.2_5.2.18-124319_Debian_stretch_amd64.deb

3.可能會出現如下問題：

root@debian:/home/kevin/下載# dpkg -i virtualbox-5.2_5.2.18-124319_Debian_stretch_amd64.deb 
(正在讀取數據庫 ... 系統當前共安裝有 159348 個文件和目錄。)
正準備解包 virtualbox
 
-5.2_5.2.18-124319_Debian_stretch_amd64.deb  ...
正在將 virtualbox-5.2 (5.2.18-124319~Debian~stretch) 解包到 (5.2.18-124319~Debian~stretch) 上 ...
正在設置 virtualbox-5.2 (5.2.18-124319~Debian~stretch) ...
addgroup: 組"vboxusers"已經是系統組。退出。
Created symlink /etc/systemd/system/multi-user.target.wants/vboxdrv.service → /lib/systemd/system/vboxdrv.service.
Created symlink 
 
/etc/systemd/system/multi-user.target.wants/vboxballoonctrl-service.service → /lib/systemd/system/vboxballoonctrl-service.service.
Created symlink /etc/systemd/system/multi-user.target.wants/vboxautostart-service.service → /lib/systemd/system/vboxautostart-service.service.
Created symlink /etc/systemd/system/multi-user.target.wants/vboxweb-service.service → /lib/systemd/system/vboxweb-service.service.
This system is currently not set up to build kernel modules.
Please 
 
install the gcc make perl packages from your distribution.
Please install the Linux kernel "header" files matching the current kernel
for adding new hardware support to the system.
The distribution packages containing the headers are probably:
    linux-headers-amd64 linux-headers-4.9.0-8-amd64
This system is currently not set up to build kernel modules.
Please install the gcc make perl packages from your distribution.
Please install the Linux kernel "header" files matching the current kernel
for adding new hardware support to the system.
The distribution packages containing the headers are probably:
    linux-headers-amd64 linux-headers-4.9.0-8-amd64

There were problems setting up VirtualBox.  To re-start the set-up process, run
  /sbin/vboxconfig
as root.
正在處理用於 systemd (232-25+deb9u4) 的觸發器 ...
正在處理用於 mime-support (3.60) 的觸發器 ...
正在處理用於 hicolor-icon-theme (0.15-1) 的觸發器 ...
正在處理用於 shared-mime-info (1.8-1+deb9u1) 的觸發器 ...
Unknown media type in type ‘all/all‘
Unknown media type in type ‘all/allfiles‘

上面已經提示我們缺少gcc make perl 包，linux的內核頭文件：linux-headers-amd64 linux-headers-4.9.0-8-amd64

我們只需要安裝即可：

sudo apt-get install gcc
sudo apt-get install make
sudo apt-get install perl
sudo apt-get install linux-headers-amd64
sudo apt-get install linux-headers-4.9.0-8-amd64

最後執行：

sudo /sbin/vboxconfig

至此Virtual Box應該無大問題。

另外Virtual Box還有USB的拓展包可以去官網查看安裝。

debian 9 安裝Virtual Box