Considering the differential successes and failures in adult second language acquisition (SLA), many researchers have urged that studies on L2 ultimate attainment should identify the domains in which adult L2 learners are (or are not) able to attain native-like proficiency levels, hence providing a descriptive basis for the learning potential in adult SLA. In particular, both Birdsong (2005) and Sorace (2005) contend that at the L2 end-state, the fundamental difference between native speakers and highly proficient late L2 learners often reside in the processing system, thereby leading to minor quantitative and/or qualitative departures from monolingual norms. To test the above claim, this study explored whether a nativelike lexical processing system can be attained by advanced L2 learners who start acquiring Mandarin Chinese as a foreign language long after the onset of puberty. To this end, the study employed the advanced-learner approach, recruiting 23 adult L2 Chinese learners, whose L2 reading skills were comparable to native Chinese speakers, and 23 native speakers of Chinese as controls. Two online reading tasks that aimed to tap into sentence-level Chinese character recognition were administered to the participants. Data revealed that, while the two groups were comparable in terms of their overall Chinese reading ability, both similarities and differences co-existed between them with regard to the underlying lexical processing procedure and the nature of the activated lexical information; nevertheless, these L2 learners were still able to achieve functional equivalence with natives at the performance level. Based upon these findings, implications for L2 end-state lexical processing system will be discussed.