An upper cover of a cover body of a high-frequency high-speed transmission cable module, comprising: a main body, two ends in the length direction of the main body being respectively defined as a first end and a second end, and the first end of the main body being disposed with a through hole; and a heat dissipation block, embedded in the through hole and exposed to a top surface of the first end of the main body; characterized in that an inner wall of the through hole is disposed with a protruding support portion, and the support portion divides the through hole into a first passage and a second passage, the first passage runs through the top surface of the first end of the main body and the second passage runs through the bottom surface of the first end of the main body, and the support portion is disposed with a connecting passage for communicating between the first passage and the second passage; and in that the heat dissipation block includes a top portion, a middle portion, and a bottom portion, and the top portion of the heat dissipation block is located in the first passage, the top surface of the top portion of the heat dissipation block is exposed to the top surface of the first end of the main body, an outer side of the bottom surface of the top portion of the heat dissipation block abuts against the top surface of the support portion, and the middle portion of the heat dissipation block is disposed at the bottom surface of the top portion of the heat dissipation block and is located in the connecting passage; the bottom portion of the heat dissipation block is disposed on the bottom surface of the middle portion of the heat dissipation block and is located in the second passage, the diameter of the top portion of the heat dissipation block is greater than the diameter of the middle portion of the heat dissipation block, and the diameter of the middle portion of the heat dissipation block is greater than the diameter of the bottom portion of the heat dissipation block. a main body, two ends in the length direction of the main body being respectively defined as a first end and a second end, and the first end of the main body being disposed with a through hole; and a heat dissipation block, embedded in the through hole and exposed to a top surface of the first end of the main body; characterized in that an inner wall of the through hole is disposed with a protruding support portion, and the support portion divides the through hole into a first passage and a second passage, the first passage runs through the top surface of the first end of the main body and the second passage runs through the bottom surface of the first end of the main body, and the support portion is disposed with a connecting passage for communicating between the first passage and the second passage; and in that the heat dissipation block includes a top portion, a middle portion, and a bottom portion, and the top portion of the heat dissipation block is located in the first passage, the top surface of the top portion of the heat dissipation block is exposed to the top surface of the first end of the main body, an outer side of the bottom surface of the top portion of the heat dissipation block abuts against the top surface of the support portion, and the middle portion of the heat dissipation block is disposed at the bottom surface of the top portion of the heat dissipation block and is located in the connecting passage; the bottom portion of the heat dissipation block is disposed on the bottom surface of the middle portion of the heat dissipation block and is located in the second passage, the diameter of the top portion of the heat dissipation block is greater than the diameter of the middle portion of the heat dissipation block, and the diameter of the middle portion of the heat dissipation block is greater than the diameter of the bottom portion of the heat dissipation block.