"高原印第安人的" can be translated as "Highland (or Plateau) Indian (people's)" in English.
Here, “高原” is translated as “Highland” or “Plateau” depending on the specific context or preference, and “印第安人的” is translated as “Indian (people's)”. If referring specifically to the people or their culture, you might use “Highland/Plateau Indians” or “the people of the Highland/Plateau Indians”.
For example:
The culture of the Highland Indians is rich and diverse.（高原印第安人的文化丰富多样。）
The Plateau Indians have a unique way of life.（高原印第安人有着独特的生活方式。）