In order to identify the dependencies and conflicts among functional safety, safety of the intended functionality and cyber security within the domain of automotive electronics and electrical fields, and to establish a unified safety framework and analysis specifications, this paper proposes a research on a phased analysis method of safety fusion concepts based on collaborative trees analysis. Hazard analysis and risk assessment are conducted by defining collaborative-related items, utilizing collaborative Hazard Analysis and Risk Assessment (HARA) or collaborative Technical Safety Analysis (TARA) to ascertain safety goals. Subsequently, through the integration of Fault Tree Analysis (FTA) and Causal Tree Analysis (CTA), functional safety and safety of the intended functionality goals are systematically decomposed. The overall safety goal is further broken down into events associated with functional safety and safety of the intended functionality; The fusion of Fault Tree Analysis (FTA) with Attack Tree Analysis (ATA) is employed to decompose the functional safety and information security goals. This process dissects the overall safety goals into events related to functional safety and cyber security, providing a basis and prerequisite for subsequent collaborative design. Finally, the fusion safety goals are derived based on the collaborative safety goals derived from the collaborative analysis. The proposed fusion analysis method can comprehensively consider the interrelationships and constraints of various types of safety, improve overall safety, form a standardized and unified safety framework, and improve development efficiency.