Panel Indicator uses 25% cpu

I suggest you report a bug

I assume that "panel-6-indicat" is not the full process name, but cut off in the display of the top command. Perhaps it is "panel-6-indicator".

What is the output of the command
ps ax | grep panel

I do not find any Ubuntu package that provides an executable with a name containing "panel-6-indicat", so there is the question whether you maybe have installed that program from some foreign source?

$ top
  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
 2183 romik 20 0 446808 35028 26832 S 21,3 0,9 2:21.52 panel-6-indicat

$ ps ax | grep panel
 2183 ? Rl 0:43 /usr/lib/x86_64-linux-gnu/xfce4/panel/wrapper-2.0 /usr/lib/x86_64-linux-gnu/xfce4/panel/plugins/libindicator-plugin.so 6 16777271 indicator Индикаторы Предоставляет место на панели для индикаторов Unity. Индикаторы позволяют приложениям и системным сервисам показывать свой статус и взаимодействовать с пользователем.

$ dpkg -S /usr/lib/x86_64-linux-gnu/xfce4/panel/plugins/libindicator-plugin.so
xfce4-indicator-plugin: /usr/lib/x86_64-linux-gnu/xfce4/panel/plugins/libindicator-plugin.so

$ apt-cache show xfce4-indicator-plugin
Package: xfce4-indicator-plugin
Priority: optional
Section: universe/xfce
Installed-Size: 370
Maintainer: Xubuntu Developers <email address hidden>
Original-Maintainer: Debian Xfce Maintainers <email address hidden>
Architecture: amd64
Version: 2.3.3-0ubuntu4
Provides: indicator-renderer
Depends: libc6 (>= 2.4), libdbus-glib-1-2 (>= 0.78), libgdk-pixbuf2.0-0 (>= 2.22.0), libglib2.0-0 (>= 2.37.3), libgtk-3-0 (>= 3.6), libido3-0.1-0 (>= 13.10.0daily13.06.19), libindicator3-7 (>= 0.4.90), libxfce4panel-2.0-4 (>= 4.11.0), libxfce4ui-2-0 (>= 4.11.0), libxfce4util7 (>= 4.9.0), libxfconf-0-2 (>= 4.6.0), upstart
Filename: pool/universe/x/xfce4-indicator-plugin/xfce4-indicator-plugin_2.3.3-0ubuntu4_amd64.deb
Size: 60824
MD5sum: ab1d273990915238c7fca0ea67c074f5
SHA1: ca96db3e21960cf1b36b66a444368e7749c4dc3d
SHA256: 2c1a4193aa68dfce9bcb4f37ea663d245815ee85457d7eb8f2d16fded72e90fa
Description-ru: модуль отображения информации от приложений на панели Xfce4
 Небольшое расширение для последовательного отображения информации от
 различных приложений в панели Xfce4 по правилам описанным в спецификации
 Ubuntu MessagingMenu design.
Description-md5: 9840efa394a05eab71be8c0a6217040f
Homepage: http://goodies.xfce.org/projects/panel-plugins/xfce4-indicator-plugin/
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu
Supported: 3y
Task: xubuntu-core, xubuntu-desktop, mythbuntu-frontend, mythbuntu-desktop, mythbuntu-backend-slave, mythbuntu-backend-master, ubuntustudio-desktop-core, ubuntustudio-desktop

P.S. I use xfce4 + compiz

This question is for xfce4-indicator-plugin package. Is there way to move it where?

The command line executed apparently is
/usr/lib/x86_64-linux-gnu/xfce4/panel/wrapper-2.0 /usr/lib/x86_64-linux-gnu/xfce4/panel/plugins/libindicator-plugin.so

The xfce4/panel/wrapper-2.0 binary is setting the process name during execution, I assume to the value "panel-6-indicato" (16 characters).

You might try re-installing the involved packages (xfce4-panel and xfce4-indicator-plugin).

"...killing the panel-6-indicat doesn't help..."
You might try killing that process via its (assumed) full name "panel-6-indicato" or using the process ID that you got via ps ax.

I was killing it by pid shown by top. The Indicators are hidden from the panel for a while and then restarted.
Reinstalling xfce4-panel and xfce4-indicator-plugin doesn't help. I have 18-28% CPU usage by indicators always (and immediately after rebooting).

"...This question is for xfce4-indicator-plugin package. Is there way to move it where?..."
Open https://answers.launchpad.net/ubuntu/+source/xfce4/+question/293837/+edit
and change the package to xfce4-indicator-plugin

I do not see much what we can for you in the question area, I suggest that you create a bug report (if you have not yet done so) and let the developers have a look at your problem.