Aiming at the problem  that the  fuel  of L NG  power ed co ntai ner sh ip re leases m ore cold energy an d was no t use d, a set of LN G c old e nergy cascad e utilization s cheme was de- signe d to use L NG col d ene rgy in refrigerate d contain er sys- tem, ship cold storage and air conditioning system. AspenHYSY S so ftwar e was used t o s imu late the  syst em process,  and obtain the main par amete rs of ke y no des. By calculat ion, the exergy effic iency o f w hole syste m an d main eq ui pment was ob- tain ed, an d a ime d at im proving th e efficie ncy of whole sys tem and based on t he exergy effi ciency of e ac h cool ing syst em, the key parameters affe cting the efficien cy of ea ch c ooling syst em were a naly zed, and then the whole s ystem was o ptimiz ed to obt ain the b est op erating par amete rs. The resu lts s how that the increa se of the ref rige rant in let tempe rature c an i mprove the ex ergy efficiency of the reefer conta iner system, the reduc- tion of th e r efrig erant in let te mperatu re c an improve the e xergy effici ency of the ship’s col d storag e and air- co ndit ioning sys- tem , after o ptimization , the ex ergy effi ciency of the who le sys- tem reaches 27. 61%, which is 4. 61% higher than that before opti mization.