Lexical stress is an important contributor to foreign accent as well as intelligibility of second language (L2) speech. The present study intends to find out to what extent Chinese-speaking learners whose native language has less evident stress can acquire English lexical stress. A production test was administered to nine advanced Chinese learners of English and nine native English controls, who read aloud 12 types of nonce English nouns. The results showed that the Chinese participants were able to place stress correctly in two-syllable words and three-syllable words with a heavy penultimate syllable. However, irregularity was observed in three-syllable words with a light penultimate syllable, particularly H(eavy)L(ow)L(ow). The results are further interpreted in Optimality Theory. It is argued that the learners' interlanguage grammar is both negatively and positively influenced by their native language. The constraint only active in Chinese causes the interlanguage to be non-nativelike. By contrast, the shared active constraints facilitate learning. Moreover, the emergence of the constraints in the interlanguage grammar which are inactive in Chinese but active in English provides evidence for the learners' ability to restructure their interlanguage phonology.