Viewing source of your login form, you have third-party plugin which controls the registration in your site and is in all probability causing the conflict. In addition, you have some plugins which have not been updated for BP 1.5.
Deactivate all plugins except BuddyPress and change to bp-default theme. Then check if registration process is corrected.
@mercime This problem started after I installed pie-register, now I have deactivated pie-register, but the problem persist, before installing that plugin, users were redirected to homepage, and after I installed pie register, users were redirected to /wp-login and even now When I deactivated the plugin, users are redirected wp-login and homepage. As u said, I am deactivating all plugin except buddypress, and my theme is already bp-default, but after I finish with deactivating procedure, where will I be able to check registration process? I am new to wordpress/buddypress, please suggest.
== This problem started after I installed pie-register, ==
Pie register is not compatible with BuddyPress.
== before installing that plugin, users were redirected to homepage ==
Were you using a custom theme or a members-only or privacy plugin during that time?
== but after I finish with deactivating procedure, where will I be able to check registration process? ==
Log out first. Then click on the link “Create an account” on the right sidebar of the default theme using a different email address.
