The invention provides a pressure-compensation variable-cross-section special shaped spray head, which consists of four parts, namely a rotary sealing mechanism, a flow passage, a pressure compensation mechanism and a rocker-arm mechanism, wherein a key part is the pressure compensation mechanism; the pressure compensation mechanism is formed by sequentially combining and connecting a special shaped nozzle, a connecting piece, a sealing piece, a water baffle and a spring; and the water baffle is obliquely arranged at a certain angle in the flow passage so as to break down the impact force of water flow into downward component force and forward component force. When the pressure of the water flow increases and the downward component force surpasses the elastic force of the spring, the spring is compressed, the water baffle moves down, and the section of a nozzle exit enlarges. When the pressure of the water flow decreases and the elastic force of the spring surpasses the downward component force, the water baffle is reset upwards under the acting force of the spring, and the section of the nozzle exit reduces. The displacement amount of the water baffle is proportional to the change magnitude of incoming-flow pressure. Aiming at the problem of pressure fluctuation, the spray head realizes pressure compensation by a method of changing the exit section, improves spray uniformity, and has the advantages of simple structure, stabler performance, more uniform spray and the like.