The invention discloses a heat forming machine and a connecting rod mechanism thereof. The connecting rod mechanism comprises two connecting rods, two movable rods and a hydraulic cylinder. The two connecting rods are symmetrically arranged, the top of each connecting rod is connected to the hydraulic cylinder through one movable rod, and the connecting mode of the movable rods, the connecting rods and the hydraulic cylinder is shaft connection; when the hydraulic cylinder extends outsides, the two movable rods keep in the same line; when the hydraulic cylinder contracts, the two connecting rods lean towards the opposite sides driven by the respective movable rod. The invention utilizes the principle that forces are mutually counteracted in the same line with the opposite directions to design an eudipleural structure, and can ensure a passive mode which is arranged on the top end of each connecting rod to be fixed and stationary in the heat forming process only needing one hydraulic cylinder. Output power of the hydraulic cylinder does not need to be too large, thereby not only the structure of the heat forming machine is simplified, but also the cost is saved.