Objective To evaluate the impact of nutritional risk-screening, assessment and support action (NRASA plan) on the initiation time of nutritional therapy, nutritional status and clinical outcomes in elderly patients with respiratory diseases. Methods A single-center, prospective, non-randomized controlled cohort study was conducted. A total of 284 elderly patients admitted to Department of Respiratory and Critical Care Medicine of a tertiary hospital from June to December 2022 were consecutively enrolled, and divided into a NRASA group (n=140) and a conventional consultation group (n=144) based on the nutritional management protocol. The initiation time of nutritional therapy, changes in nutritional indicators, hospitalization costs and prognostic indicators were compared between the two groups. SPSS statistics 27.0 was used for statistical analysis. Data comparison between two groups was performed using t test, Mann-Whitney U test, χ² test or Fisher′s exact probability test depending on data type. Results The initiation time of nutritional therapy in the NRASA group was significantly shorter than that in the conventional group [3.0 (2.0,4.0) vs 6.0 (3.0,11.5) d, P<0.05]. After nutritional therapy, the levels of total protein (TP), albumin (Alb), and high-density lipoprotein cholesterol (HDL-C) in the NRASA group were obviously higher than those in the conventional group [(65.76±8.10) vs (62.11±9.08) g/L, (36.64±5.11) vs (34.17±5.02) g/L, (1.02±0.48) vs (0.86±0.52) mmol/L; all P<0.05)]. Nutritional therapy resulted in significant increases in the levels of TP, Alb, total cholesterol (TG), and HDL-C in the NRASA group [(65.76±8.10) vs (59.32±9.45) g/L, (36.64±5.11) vs (32.27±6.10) g/L, (3.66±1.11) vs (3.29±1.19) mmol/L, (1.02±0.48) vs (0.84±0.44) mmol/L; all P<0.05]. While, in the conventional group, the level of hemoglobin (Hb) was notably decreased, while those of TP and Alb were increased after treatment [(102.00±21.64) vs (107.81±21.82) g/L, (62.11±9.08) vs (59.89±8.77) g/L, (34.17±5.02) vs (32.57±5.87) g/L; all P<0.05)]. The NRASA group had remarkably lower total hospitalization cost, parenteral nutrition cost, length of hospital stay, and incidence of gastrointestinal bleeding than the conventional group [5.52 (3.08,10.59) ×10⁴ vs 5.95 (2.37,10.46) ×10⁴ yuan, 0.15 (0.08,0.32) ×10⁴ vs 0.22 (0.09,0.45) ×10⁴ yuan, 19.0 (14.0,28.0) vs 21.5 (16.0,31.0) d, 1.4% (2/140) vs 6.3% (9/144); all P<0.05]. Conclusion The NRASA plan, through multidisciplinary collaboration and standardized processes, effectively reduces the delay of nutritional treatment, improves the nutritional and metabolic indicators of patients and decreases medical costs, providing practical evidence for standardized nutritional management in elderly patients with respiratory diseases.