<p>In-situ consolidation (ISC) is a highly efficient and cost-effective technology that holds great promise for the manufacturing of thermoplastic composite structures. However, the use of localized heating during ISC inevitably introduces significant temperature and strain gradients. Accurate measurement of temperature and strain using fiber Bragg grating (FBG) sensors is essential for process optimization and control. Yet, the rapidly evolving and highly non-uniform thermal fields present in ISC pose substantial challenges to the decoupling of temperature and strain signals in FBG sensing. In this paper, a novel proxy-point decoupling method for multipoint temperature and strain monitoring is proposed. In this method, based on the premise of spatially repeatable temperature histories along the layup path, temperature data acquired at a remote point are used to compensate strain values at a nearby location, for the first time, enabling online, multipoint, and simultaneous monitoring of temperature and strain both in-plane and through-thickness during the ISC process. We refer to the points used for acquiring temperature data as proxy-point. Building on this approach, the study investigates the through-thickness distributions of temperature and stress, analyzes the residual strain in the manufactured components, and reveals the evolution mechanisms of temperature, stress, and strain during ISC process. The deformation behavior of the composite structures is further elucidated, offering technical references for temperature control in ISC processes.</p>