Abstract: In aircraftps overall plan design phase, designers have to evaluate the technology maturity of the composite aircraft structure to determine whether the composite will be applied to the given component . A quantitative evaluation method for technology maturity of composite aircraft structure (TEMCAS) is proposed according to technology readiness levels (TRL) standard. This evaluation method divides the technology maturity of the advanced composite aircraft structure into eight scales, covering all research and development processes, i. e. from demand research to production application. This method was further applied to evaluate the technology maturity of advanced technology fuselage composite of Boeing Company. It can be applied in the overall plan design phase to reduce the risk of aircraft-development and the impact of compositeps application on aircraft-development schedule.