Abstract: Microminiature refrigerator(MMR)is wildly used in micro element cooling area.It is fabricated by novel etching,material growing,thinning and bonding technologies.The minimum size of its restriction area can be 1 μm.This paper presents a numerical optimization by employing the multi-objective method to obtain the best structural parameters with the goal of optimizing the MMRs high and low-pressure heat exchangers’heat transfer and pressure performance.The calculation results agree well with correlations in literature.The results showed that compared to the origin model the Nus-selt number Nu is increased by 5.8% and friction factor f is decreased by 25.7% in optimized high-pressure heat exchanger model,as for the optimized low-pressure heat exchanger model the Nu is increased by 14.5% and f is decreased by 2.3%.The patterns of Nu and f change with structural parameters are also obtained.This paper provides a new approach of MMR heat exchangers simulation and offers theoretical reference to the performance optimization.