A circular light-guiding structure, comprising: a hollow-out portion; and a light-guiding portion, the light-guiding portion being disposed on an outer peripheral side of the hollow-out portion, having light transmissibility, and comprising four light source receiving slots and four trenches and a plurality of microstructures, and the four light source receiving slots are arranged at intervals at an inner peripheral side of the light-guiding portion and in communication with the hollow-out portion, each light source receiving slot having a light source disposition position, and the four trenches being respectively disposed outside the four light source receiving slots, a direct distance between two ends of each trench being greater than width of each light source receiving slot, and the microstructures being disposed in a protruding manner from bottom surface of the light-guiding portion; wherein the microstructures are divided into four sets of microstructure assembly, each set of microstructure assembly comprises a plurality of microstructures, and a part of microstructures of each set of microstructure assembly are curved concentric structures with different radii centered on the light source disposition position of each light source receiving slot; a light circle, the light circle having light transmissibility and comprising a light-reflecting portion and a light-emitting portion; the light-reflecting portion being disposed around an outer peripheral side of the light-guiding portion and having a light-reflecting surface, and the light-emitting portion being disposed above the light-reflecting portion; wherein the light source disposition position of each light source receiving slot, an intermediate position of a longitudinal direction of each trench and a position of a minimum distance of an inner peripheral side of the light-reflecting portion are on the same straight line; and wherein the light-guiding portion is partitioned into four light-guiding regions, and one inner peripheral side of each light-guiding region has two planes (1205, 1206), and the two planes (1205, 1206) of each light-guiding region are respectively connected with a slot wall of one of the light source receiving slots, and the two planes (1205, 1206) of each light-guiding region extend in a longitudinal direction and form an angle (Θ1) at intersection, the angles of the four angles (Θ1) are equal and between 165° and 180°, and the adjacent two light-guiding regions form a rounded corner between the two planes (1205, 1206). a hollow-out portion; and a light-guiding portion, the light-guiding portion being disposed on an outer peripheral side of the hollow-out portion, having light transmissibility, and comprising four light source receiving slots and four trenches and a plurality of microstructures, and the four light source receiving slots are arranged at intervals at an inner peripheral side of the light-guiding portion and in communication with the hollow-out portion, each light source receiving slot having a light source disposition position, and the four trenches being respectively disposed outside the four light source receiving slots, a direct distance between two ends of each trench being greater than width of each light source receiving slot, and the microstructures being disposed in a protruding manner from bottom surface of the light-guiding portion; wherein the microstructures are divided into four sets of microstructure assembly, each set of microstructure assembly comprises a plurality of microstructures, and a part of microstructures of each set of microstructure assembly are curved concentric structures with different radii centered on the light source disposition position of each light source receiving slot; a light circle, the light circle having light transmissibility and comprising a light-reflecting portion and a light-emitting portion; the light-reflecting portion being disposed around an outer peripheral side of the light-guiding portion and having a light-reflecting surface, and the light-emitting portion being disposed above the light-reflecting portion; wherein the light source disposition position of each light source receiving slot, an intermediate position of a longitudinal direction of each trench and a position of a minimum distance of an inner peripheral side of the light-reflecting portion are on the same straight line; and wherein the light-guiding portion is partitioned into four light-guiding regions, and one inner peripheral side of each light-guiding region has two planes (1205, 1206), and the two planes (1205, 1206) of each light-guiding region are respectively connected with a slot wall of one of the light source receiving slots, and the two planes (1205, 1206) of each light-guiding region extend in a longitudinal direction and form an angle (Θ1) at intersection, the angles of the four angles (Θ1) are equal and between 165° and 180°, and the adjacent two light-guiding regions form a rounded corner between the two planes (1205, 1206).