A cartilage substitute, implantable into a target bone, the target bone being cooperated with a corresponding bone, the cartilage substitute comprising at least one cartilage unit, the cartilage unit comprising: a base, comprising a subcutaneous layer portion forming contact friction with the corresponding bone, a deep layer area portion contacting with the target bone and an intermediate layer portion disposed between the subcutaneous layer portion and the deep layer area portion, a first opening being formed in an outer surface of the subcutaneous layer portion and a second opening being formed in an inner surface of the deep layer area portion; a fluid storage cavity, disposed in the subcutaneous layer portion and communicated with the first opening and the second opening respectively, a fluid being capable of being stored in the fluid storage cavity and flowing out of the base through the first opening and the second opening; a first communicating passage, disposed in the subcutaneous layer portion and communicating the fluid storage cavity and the first opening; and characterized in that the cartilage unit further comprises: second communicating passages and third communicating passages, communicating the fluid storage cavity and the second opening, the second communicating passages being disposed in the intermediate layer portion, the third communicating passages being disposed in the deep layer area portion and a distribution density of the second communicating passages being higher than a distribution density of the third communicating passages, wherein a cross sectional area of the fluid storage cavity is bigger than a sum of cross sectional areas of the second communicating passages and the sum of cross sectional areas of the second communicating passages is bigger than a sum of cross sectional areas of the third communicating passages, so as to make a hardness of the subcutaneous layer portion lower than a hardness of the intermediate layer portion and make the hardness of the intermediate layer portion lower than a hardness of the deep layer area portion. a base, comprising a subcutaneous layer portion forming contact friction with the corresponding bone, a deep layer area portion contacting with the target bone and an intermediate layer portion disposed between the subcutaneous layer portion and the deep layer area portion, a first opening being formed in an outer surface of the subcutaneous layer portion and a second opening being formed in an inner surface of the deep layer area portion; a fluid storage cavity, disposed in the subcutaneous layer portion and communicated with the first opening and the second opening respectively, a fluid being capable of being stored in the fluid storage cavity and flowing out of the base through the first opening and the second opening; a first communicating passage, disposed in the subcutaneous layer portion and communicating the fluid storage cavity and the first opening; and characterized in that the cartilage unit further comprises: second communicating passages and third communicating passages, communicating the fluid storage cavity and the second opening, the second communicating passages being disposed in the intermediate layer portion, the third communicating passages being disposed in the deep layer area portion and a distribution density of the second communicating passages being higher than a distribution density of the third communicating passages, wherein a cross sectional area of the fluid storage cavity is bigger than a sum of cross sectional areas of the second communicating passages and the sum of cross sectional areas of the second communicating passages is bigger than a sum of cross sectional areas of the third communicating passages, so as to make a hardness of the subcutaneous layer portion lower than a hardness of the intermediate layer portion and make the hardness of the intermediate layer portion lower than a hardness of the deep layer area portion. second communicating passages and third communicating passages, communicating the fluid storage cavity and the second opening, the second communicating passages being disposed in the intermediate layer portion, the third communicating passages being disposed in the deep layer area portion and a distribution density of the second communicating passages being higher than a distribution density of the third communicating passages, wherein a cross sectional area of the fluid storage cavity is bigger than a sum of cross sectional areas of the second communicating passages and the sum of cross sectional areas of the second communicating passages is bigger than a sum of cross sectional areas of the third communicating passages, so as to make a hardness of the subcutaneous layer portion lower than a hardness of the intermediate layer portion and make the hardness of the intermediate layer portion lower than a hardness of the deep layer area portion.