The possibility of optimization of a pulse cryocooler with a cooling temperature of 80 K is investigated. The parameters of the cryocooler were evaluated taking into account the peculiarities of heat exchange and pressure losses at oscillating gas flow in the regenerator in the Regen 3.3 package. The aim of the study is to determine the optimal design and operating parameters of the regenerator, at which the greatest efficiency of the cooler will be obtained. The influence of such factors as the frequency of oscillation of the working body, phase shift, reverse mass flow rate, and the length of the regenerator on the operating parameters of the gas in the regenerator was investigated. During modelling using REGEN 3.3 the changes of basic variables resulting in significant change of the pulse cryocooler characteristics were revealed. As a result of optimization the values of operating parameters were obtained, at which the maximum value of efficiency of 0.132 was achieved. For a given level of cooling capacity and cooling temperature of 80 K, the following parameters of the cryocooler were obtained: regenerator length 0.045 m, oscillation frequency 40 Hz, phase shift –40o, reverse mass flow rate 0.145 m2/(kg/s). The results of the study can be used in the design of a regenerator for gas cryogenic machines, and also demonstrate the influence of the regenerator parameters on the cooling capacity and efficiency of the cooler.