With the widespread application of embedded systems, their requirements are becoming increasingly complex, and requirements analysis has become a key stage in the development of embedded systems. How to accurately model and describe requirements has become the primary issue. This paper systematically investigates the requirements description of embedded systems and conducts a comprehensive comparative analysis in order to gain a deeper understanding of the core concerns of embedded system requirements. First, a systematic literature review method is adopted to identify, screen, summarize, and analyze the relevant literature published between January 1979 and November 2023. Through automatic retrieval and snowballing, 150 papers closely related to the topic were selected to ensure the comprehensiveness of the literature review. Secondly, from the aspects of requirements description focus, requirements description dimension, and requirements analysis elements, the expressive ability of existing embedded requirements description languages is analyzed. Finally, the challenges faced by the current software requirements description of embedded systems are summarized, and the requirements for the expressive ability of the requirements description method for embedded systems are put forward for the task of intelligent synthesis of embedded software.