Objective To develop a simplified Chinese version of Triage and Acuity Scale(TAS) with an electronic decision support tool and to test the reliability and validity. Methods The simplified Chinese version of TAS was developed by forward translation and expert group discussion based on Taiwan Triage and Acuity Scale (TTAS), then a computerized decision support system was created.The reliability and validity of the simplified Chinese version of TAS were tested in a convenience sample of 2 058 emergency patients attending a tertiary hospital in Changsha. Results The inter-rater reliability was 0.822 and the content validity index was 0.982. Predictive validity showed that hospitalisation rate, medical resource consumption, medical costs and length of stay in emergency department had significant differences among different TAS triage acuity levels （P＜0.01 for all）. Conclusion The electronic triage system based on the simplified Chinese version of TAS has high inter-rater reliability, content validity and predictive validity.The system can accurately prioritize patients on the basis of the urgency of interventions, and each functional module meets the actual needs and can be put into clinical practice.