Abstract: It is hard and challenging to work in Intensive Care Unit. Clinical manager has been focused on the efficient evaluation of nursing workload and the reasonable allocation of nursing staff, so as to optimize resource utilization and improve work efficiency. Therapeautic Intervention Scoring System (TISS) is widely used in many countries to evaluate disease severity of the patients in ICU, quantize the workload of nursing staffs, calculate scientifically the allocation, application and cost saving of ICU medical resource. This article summarizes the development and application of TISS, and introduce the usage, application as well as its limitations for clinical reference.