At least 30% of newly diagnosed people living with HIV (PLHIV) have delayed antiretroviral therapy (ART) initiation globally, resulting in irreversible impaired immune function and increased risk of HIV transmission. This study aimed to explore the decision‐making process of ART initiation in China. A phenomenological research design was used and semi‐structured, in‐depth interviews based on dual‐system theory were conducted. Participants were selected using purposive sampling between December 11, 2021 and June 25, 2022. Interpretative phenomenological analysis (IPA) was performed utilizing the software NVivo 12. A total of 34 PLHIV were interviewed. The heuristic system and the analytic system were involved in the complex decision‐making process for ART initiation. Acceptability, negative emotion, and stigma were all parts of the heuristic system. The analytic system included the perception of ART benefits, positive support, and misconception. Two systems interacted with each other in the decision‐making of ART initiation. PLHIV's initiation decision was determined by the components of the dominant system. This theory‐driven qualitative study provided valuable insights on the decision‐making process of ART initiation among newly diagnosed PLHIV.