I want to send my sister to a good high school in US. She's 10th
grader and currently studying in Hong Kong. Please find me information
of good public/private high schools that accept international student
and the application process? I would prefer the ones that do not
require PSAT exam and US east coast or west coast schools are
prefered. Thank you.

There are a lot of private US high schools that accept international
students, but they would generally require an SSAT test.  Public
schools would be more difficult, because they generally require that
you live in the area.

Among the private boarding schools on the East Coast would be Philips
Exeter, Philips Andover, Deerfield, Hotchkiss, and St. Paul's.  These
schools are more limited on the West Coast, but the leading one would
probably be Thacher.

See http://www.hotchkiss.org/Admission/ for a sample of admissions
requirements (basically an application with an essay, an SSAT, and an
interview with an alum in your area).

Another website that will help you find a school for you is
http://www.boardingschoolreview.com/