This study tested whether native Chinese (L1) readers whose second language (L2) was English could activate L2 translations of L1 words during L1 sentence reading. Chinese–English bilinguals read Chinese sentences silently, each containing a target word whose parafoveal preview was manipulated. To test cross-language semantic activation, each target word was paired with an identical, an unrelated and a translation-related preview that shared an L2 translation (e.g., 政黨, party as a political group) with the target word (e.g., 派對, party as a social gathering). Compared to the unrelated previews, the translation-related previews induced shorter target-word viewing times, despite no phonological/orthographic overlap. Furthermore, the highly proficient L2 readers showed earlier priming effects than did the average readers. Our results suggest that bilinguals activate lexical representations in both languages automatically and non-selectively, even when the task requires activation of one language only, and that the L2 lexical activation is modulated by L2 proficiency.