首先保证你的应用能够获取system权限：android:sharedUserId="android.uid.system"；
然后申请权限：
<uses-permission android:name="android.permission.MASTER_CLEAR"/>
<uses-permission android:name="android.permission.MOUNT_FORMAT_FILESYSTEMS"/>
调用以下代码完成格式化：
public void diskFormat() { ComponentName formatter = new ComponentName("android", "com.android.internal.os.storage.ExternalStorageFormatter"); Intent intent = new Intent("com.android.internal.os.storage.FORMAT_ONLY"); // ExternalStorageFormatter.FORMAT_ONLY intent.setComponent(formatter); Parcelable sv = getStoragePath(mContext); intent.putExtra("storage_volume", sv); // StorageVolume.EXTRA_STORAGE_VOLUME mContext.startService(intent);}// 获取 StorageVolume 对象private Parcelable getStoragePath(Context mContext) { StorageManager mStorageManager = (StorageManager) mContext.getSystemService(Context.STORAGE_SERVICE); Class<?> storageVolumeClazz = null; try { storageVolumeClazz = Class.forName("android.os.storage.StorageVolume"); Method getVolumeList = mStorageManager.getClass().getMethod("getVolumeList"); Method getPath = storageVolumeClazz.getMethod("getPath"); Method isRemovable = storageVolumeClazz.getMethod("isRemovable"); Object result = getVolumeList.invoke(mStorageManager); final int length = Array.getLength(result); for (int i = 0; i < length; i++) { Object storageVolumeElement = Array.get(result, i); String path = (String) getPath.invoke(storageVolumeElement); boolean removable = (Boolean) isRemovable.invoke(storageVolumeElement); if (removable && path.equals(mPreferUsbPath)) { return (Parcelable) storageVolumeElement; } } } catch (Exception e) { e.printStackTrace(); } return null;}
mPreferUsbPath是你需要格式化的外部存储路径，按实际替换即可。
一般MountService会默认将外部存储格式化为 EXT3 文件系统格式，当然根据定制ROM配置文件的不同也可能为其他格式。