Aiming at the problem of poor stability of self-regulated crycooler with bellows,through the force analysis of self-regulated structure of bellows,the reserved displacement is optimally designed which is the core components of the self-regulated crycooler with bellows. Self-regulation ability of the crycooler is enhanced. Mis-function of self-regulating and flow rate changing of the crycooler are avoided by design. The phenomenon of intermittent hydrojet of the self-regulated crycooler is improved. The stability of this crycooler is improved observably,which is verified through experiments.