Solar wind may contain some hydrogen and oxygen atoms which is the composition of water, some of them may move to the poles of earth, my question is, is solar wind also a source of water in earth?
Perhaps I have always been misunderstanding the concept of space weather, rain from space now that's a cool idea.
Seriously though, the solar wind particles are at such a a high temperature that molecules cannot form, instead it is an ionised gas containing mainly Hydrogen and Helium and only very tiny traces of other elements.
As awesome as space rain would be, the sun does not deposit any water molecules on earth. Solar wind consists of ionized particles propelled into space from the sun, and while some of these particles are hydrogen, and some are oxygen (http://www.spaceref.com/news/viewsr.html?pid=35448), these are ionized particles therefore incapable of bonding with each other in the manner necessary to create water. Furthermore, even if these particles did lose enough kinetic energy to reach the energy level low enough to bond to one another, it is unlikely that they would be able to do so because their high velocity, coupled with the incredibly high chance of them missing the earth and the deflective prowess of the magnetosphere would preclude such processes. If somehow enough hydrogen and oxygen atoms were low energy enough and did arrive at the poles, I doubt that they would bond, because the reaction between hydrogen and oxygen to form water requires activation energy.