In Budai Rukai, a Formosan language, primary stress exclusively falls on the rightmost, the penultimate or antepenultimate syllable of each prosodic word. More interestingly, prefixes and infixes can only bear secondary stress; they are excluded from the domain where primary stress is assigned. The goal of this paper then is to identify, compare, and account for the ways stress distribution is handled in Budai Rukai. More specifically, the present study aims to show how morpho-prosodic alignment constraints interact with other constraints to formalize the demarcative property of stress distribution in Budai Rudai.