To explore application potential of Lycium barbarum carotenoids (Lyb-C) in potato chip processing, Lyb-C was used as an additive, and fried composite potato chips (FPC) were prepared by low-temperature vacuum frying. Effects of Lyb-C dosage on sensory quality, physicochemical properties, oil distribution, and starch characteristics were systematically evaluated, and regulatory mechanism underlying potato chip quality improvement was elucidated based on microstructural observation and spectroscopic analysis. Results showed that, compared with control group, Lyb-C effectively improved the quality of FPC, imparting an orange-red appearance. FPC with 0.10% Lyb-C showed optimal performance, with the highest overall acceptability. Its color parameters a and b increased by 8.74% and 0.63%, hardness increased by 38.15%, and total oil (TO) and surface oil (SO) contents decreased by 4.43% and 2.12%, respectively. Meanwhile, starch gelatinization and retrogradation were inhibited and in vitro starch digestion was promoted. Microstructural and spectroscopic analyses indicated that Lyb-C modified microstructure of chips, producing a denser and smoother surface, which contributed to reductions in SO and TO. The interaction between Lyb-C and starch molecules markedly decreased relative crystallinity and short-range ordered structure, disrupted starch order, and enhanced enzymatic susceptibility, thereby suppressing gelatinization and retrogradation and promoting in vitro starch digestion. Overall, Lyb-C improved comprehensive quality of composite potato chips in low-temperature frying system by regulating starch structure and oil distribution, providing theoretical basis and technical support for efficient utilization of Lyb-C and development of healthier composite potato chips.