Li　metal　anode　attracts　tremendous　attention　in　next-generation　battery　systems　with　high　energy　density,　but　volume　change　and　dendritic　growth　limit　its　practical　applications.　Composite　Li　electrode　can　fundamentally　suppress　the　volume　effect　and　decrease　the　local　current　density,　ensuring　long-term　cycling　life.　However,　up　to　now,　there　is　only　limited　success　in　preparing　multifarious　composite　Li　electrode,　especially　in　thickness,　posing　great　obstacles　to　further　promoting　its　research　and　application.　In　this　review,　the　thickness　of　composite　Li　electrode　are　strategically　focussed　upon　and　the　merits　and　existing　challenges　of　ultrathin　composite　Li　electrode　are　evaluated.　Meanwhile,　the　design　principles　and　fundamental　requirements　for　ultrathin　composite　Li　electrode　in　the　future　are　summarized　and　the　existing　cases　related　to　this　field　are　outlined　as　much　as　possible　from　synthetic　chemistry,　hoping　it　can　serve　as　a　handbook　to　provide　a　comprehensive　understanding　and　guide　reliable　fabrication　of　advanced　composite　Li　electrode.　Challenges　and　opportunities　regarding　this　burgeoning　field　are　also　critically　evaluated　at　the　end　of　this　review.