Neutron logging-while-drilling is a nuclear logging technique within the logging-while-drilling (LWD) system, characterized by high sensitivity to hydrogen formation. With the increasing complexity of well trajectories and the development of unconventional oil and gas, it has evolved from a traditional porosity measurement tool into a critical source of real-time information for geosteering and engineering decision-making. From a systems engineering perspective, this paper reviews the physical basis, tool system configuration, data processing methods, and typical engineering applications of LWD neutron logging. It discusses key technical bottlenecks and development trends. The results indicate that multiple interacting factors, including the neutron source, detector configuration, measurement geometry, environmental suppression capability, and interpretation strategy, constrain its performance. The transition from chemical neutron sources to pulsed neutron generators (PNG) represents a critical turning point, improving measurement safety and expanding the range of measurable parameters while simultaneously introducing new engineering challenges such as target material lifetime and long-term stability. Field practice further demonstrates that the main value of LWD neutron logging lies in providing real-time porosity and related information that overcomes physical limitations during drilling, supporting geosteering and real-time reservoir evaluation decisions. Based on current progress, future work will focus on enhancing the reliability of PNG-based neutron sources and developing data processing and intelligent interpretation workflows that integrate physical models with data-driven methods.