This is a practice-based research, in the process of creating Ketchup（《番茄酱》）, a short work of animated documentary as an exploration of autobiographical memory and trauma memory, the author also experimented with the narration structure and visual metaphor in animated documentary. Since a series of important animated documentary works were first produced starting in 1995, including Drawn from Memory(Paul Fierlinger,1995), Sunrise over Tiananmen Square (Shuibo Wang, 1999) and Waltz with Bashir (Ari Folman,2008), animated documentary has revealed a new style of narration for the author themselves, and at the same time a device for social criticism. By using “first person” perspective or even voices, animated documentary can deeply rethink and question social problems and historical trauma. This paper focuses on the spectrum of memory, including the taste of memory, the color of memory, the structure of memory and the metaphor of memory, these aspects of memories will be explored deeply through the cross-dialogue between the above art works and a series of animated documentaries from east European countries. The key point of research of animated documentary also relies on rethinking and redefining what animated documentary is, this paper demonstrates animated documentary is already beyond the discussion of ontology of animation or documentary, it is a new entity with its own identity and potential.