I am 26 years old. I have an ocd disease since 2 years and also depression.depression is OK but ocd doesn't go from my mind. Many thoughts comes to my mind.my mind say again and again you go and wash your hand .my mind thoughts no one touch me because they are dirty or dusty like. I'm very worried about this.so please give me advice or islamic way that can help to remove ocd from the roots.

You should be seeing someone trained in dealing with this. You are never going to achieve the same results trying to deal with this without them.

There are several ways to deal with this, unfortunately they're best administered and described by your medical professional. I would talk to the medical professional that diagnosed your OCD and get treatment from him. Could be drugs or behavioural treatment, either way it is better to be administered and monitored by a medical professional.

http://www.psychiatryadvisor.com/anxiety/emerging-effective-ocd-therapy/article/514725/

Please read that and ask questions. The drugs are names as sold in the US. Notice especially the use of ketamines or DCS.
Very strong OCD really does benefit most from the right drugs, but you need good talk therapy too.
The second page of the article mentions the part that habit plays.

I agree with the others that the guidance of a good health caregiver is the way to go, and the doctor who diagnosed you 2 years ago, can guide you to the right therapist, counselor, or doctor.

You can read here as it relates to Islam.

http://islamandpsychology.blogspot.com/2011/08/islamic-solution-for-ocd-waswaas.html

https://www.missionislam.com/health/compulsivedisorder.htm