A plate heat exchanger is provided in the present application, which includes multiple first plates and multiple second plates which are alternately stacked together, first flow passages and second flow passages spaced from each other are formed between the first plates and the second plates, a first passage is formed by first orifices, a second passage is formed by second orifices, and the first passage and the second passage are in communication with each other via the first flow passages or the second flow passages to form a first fluid passage. At least one damping structure is provided in the first fluid passage, and at least a part of the first fluid passage is in communication with a first pipe or a second pipe via the damping structure.