Abstract: Stirling type cryocooler has been widely used in space infrared remote sensor system for its excellent properties such as low refrigeration temperature, high refrigeration efficiency, compact structure and long working life. A stirling type cryocooler, who uses one compressor drives two individual expanders, is designed to meet special space requirement. The structure and characteristics of this cryocooler are introduced. The velocity of inlet gas, which is fluctuant in fact, is simplified to be contant. By changing the intersection angles of the outlet pipelines and the inner diameters of the pipelines, several appropriate designs are seleced. The final design is selected by comparing their useless spaces and flow resistances.