Objective To establish the scoring system for assessing senile patients with respiratory failure undergoing mechanical ventilation (SRFMVs), and to evaluate the clinical efficacy of the scoring system. Methods SRFMV scoring system was established base on the SRFMV mortality rate equation. Totally 138 hospitalized senile patients who had respiratory failure and required mechanical ventilation were evaluated with the scoring system prospectively. The SRFMVs and APACHEⅡscoring system were evaluated as measures of illness severity in our study. The area under the receiver operating characteristic curve (AUROC) and the correlation analysis of survival were used to compare the predictive value of each scoring systems. Results (1) For mortality rates in the first month among patients receiving mechanical ventilation, AUROC of SRFMVs [0.89 (95%CI 0.826-0.937)] was larger than that of APACHEⅡ0.75 (95%CI 0.675-0.825)], with a statistically significant difference between these 2 score systems (Z = 3.7, P＜0.001). (2) The mortality risk of patient was low when SRFMV score was less than 74, and the negative predictive value for predicting death rate in one month was 96.4% (95%CI 86.8-99.4). However the mortality risk of patient would be high with SRFMV score higher than 98, by which the positive predictive value for predicting death rate in one month was 91.3% (95%CI 71.9-98.7). The mortality risk of patient would be ranked as intermediate when his SRFMV score was between 74 and 98.3. (3) The SFRMV score was highly correlated to the mortality rate among patient receiving mechanical ventilation (RR = 1.05, 95%CI 1.04-1.06, P＜0.01), while APACHEⅡ score failed to show correlation (P＞0.1). A significant difference in the overall survival time was observed among different groups (χ2 = 66.26, P＜0.01). The higher was the risk the shorter was the survival time. In low risk group, the median survival time was 360 days, which was 30 days in intermediate risk group and only 3 days in high risk group. Conclusion SRFMVs has high sensitivity and high specificity for the risk assessment in senile patient undergoing mechanical ventilation, and can be used to evaluate the disease severity and the prognosis in patients, which has a guidance value in clinical practice.