The prostate-specific antigen (PSA) has been widely used for the early diagnosis of prostate cancer during routine check-ups. However, the low sensitivity of regular PSA tests in the PSA gray zone often means that patients are required to undergo further invasive needle biopsy for the diagnosis of prostate cancer, which may lead to potential overdiagnosis and overtreatment. In this study, a circulating tumor cell (CTC)-chip based on an evaporation-induced reduced graphene oxide (rGO) coating is presented, which enables a highly specific and non-invasive diagnosis of prostate cancer in the PSA gray zone. During the evaporation process of the rGO dispersion, the Marangoni effect induces the self-assembly of a hierarchical micro/nanowrinkled rGO coating, which can capture CTCs after subsequent surface modification of capture agents. Compared to the low diagnostic sensitivity (58.3%) of regular PSA tests, a combination of CTC detection and PSA-based hematological tests via machine-learning analysis can greatly upgrade the diagnostic sensitivity of this disease to 91.7% in clinical trial. Therefore, this study provides a non-invasive alternative with high sensitivity for the diagnosis of prostate cancer in the PSA gray zone.© 2021 Wiley-VCH GmbH.