The utility model relates to an external heat-insulating system faced by aqueous imitated natural granite coating, which has the concrete structure that a first interface binder layer (2-1), a binding mortar layer (3), a polystyrene board heat-insulating layer (4), a second interface binder layer (2-2), a polymer anti-cracking mortar finishing layer (6) lined with glass fabric gridding cloth (5), a polymer flexible putty leveling layer (7), a smoothly-surfaced putty layer (8), a closed primer layer (9) and a facing layer (10) are sequentially arranged on the external surface of a basic wall body (1) from inside to outside. The utility model is characterized in that the facing layer (10) comprises an elastic grounding layer (10-1), an aqueous multicolor flexible pattern layer (10-2) and a cover surface protecting layer (10-3) which are sequentially arranged from inside to outside, wherein each layer is combined with the basic wall body (1) into a whole after being dried and cured. The external heat-insulating system of the utility model has the remarkable advantages in the aspects of decorative property, economical property, safety and the like.