I have remove the admin role of jasperadmin acidentially, and I find that there is no superuser account
How can i get back the admin account? Should I uninstall and re-insall jasper server?
can you try out this procedure: https://community.jaspersoft.com/wiki/how-reset-superuser-password.
If doesn't work feel free to open a support case (commercial editions) to request for a superuser account from a standard deployment into a zip file to be imported in your instance.
Hope it helps.