Rapid development of Chinese commercial launch vehicles brings new challenges under the traditional systems engineering (TSE) working method.A new model-based systems engineering (MBSE) working method was proposed for Smart Dragon I (SD-I),which is a low-cost commercial launch vehicle developed by the China Academy of Launch Vehicle Technology (CALT).Based on the characteristics of a commercial launch vehicle,the system model based on information cards was established.Through a problem-oriented working method,risk identification and management,the process of Card-MBSE was utilized and verified by the success of the maiden flight of SD-I.This paper introduces a new method and reference for the development of low-cost and high-reliability launch vehicles.