Taking the objective function of thermoeconomics and the boiler minimum heat transfer surface area, the system thermodynamics parameters and the boiler structural design parameters in accordance with three types of tube form and two kinds of tube arrangement for five typieal marine waste heat power recoyery systems (MWHPRS) of PA6 diesel areoptimized respectively. The calculated results for MWHPRS are given and the advantages and disadvantages of each system are analysed.