I'm a newbie and my English is quite bad.
Can someone tell me how linux starts to work when power on?

I think you are looking for:
startx

It sounds more like he's asking how the boot process works. Basically, the computer's BIOS loads the bootloader into memory. The bootloader parses its configuration file and (possibly) waits for user input. After some timeout, it boots the default OS. It reads the kernel off of disk (Linux kernels are compressed, so the kernel image must be uncompressed too), loads it into memory at some predetermined address, and executes a jump instruction to that address. The kernel then ges through hardware detection, initializes itself, and spawns the init process (pid 1, the first user process to run). Assuming we're using a standard init, init parses /etc/inittab to figure out what it's supposed to run. Eventually, depending on how it's configured init will launch the getty process on the console, presenting the user with the standard login prompt. It may also launch xdm, kdm, or something similar to give the user a GUI login prompt.

That's the process in a nutshell. Bt198629, if you want more detail than that, you'll need to ask a more specific question.

Depending on what boot loader you're using (grub/lilo), it goes to the screen where you choose your boot image to use for this session, you can also pass some parameters to kernel at boot if you'd like unregular boot, then init starts and enables all kinds of hardware and software, then (if you're using graphical linux distribution) the graphical server starts and you're prompted for login name and password.

Hope i didn't miss anything.

btmiller's reply is more technical, hope it wont scare you though

Thank you! I thank I have to get some books to read . Can you introduce some of this sort to me ?

Thank you! I think I have to get some books to read . Can you introduce some of this sort to me ?

Why books?

You need go no further than the LinuxQuestions.Org wiki.

A good article, referenced in the wiki, is How Linux Boots, found here...

Thank you!I will go and read it

Here is some information that might help you:
http://tille.xalasys.com/training/tldp/index.html
http://www.tldp.org/LDP/intro-linux/...tro-linux.html
http://www.linuxhq.com/guides/LUG/node2.html
http://www.tldp.org/
http://www.psychocats.net/essays/linuxguide.php
http://www.linux.org/lessons/index.html
http://www-106.ibm.com/developerworks/linux/newto/
http://www.tldp.org/HOWTO/HOWTO-INDEX/howtos.html
http://linux.org.mt/article/terminal
http://www.linux.org/lessons/beginner/toc.html
http://www.linux.org/docs/online_books.html
http://www.linuxplanet.com/linuxplan...orials/3174/1/
http://easylinuxguide.com/

Happy reading!