Abstract: In field nursery,an experiment was carried out with a Fran-kia F287 strain and seedlings from 24 different seedlots of genotypes--14provenances of Casuarina equisetifolia and 10 C.junghuhniana.The results showed that there were significant differences (P0.05 or 0.01) among genotypes,and between inoculation and non-inoculation treatments in growth and biomass production.The increment mean values of 24 Frankia-genotype associations in nodule numbers,growth and biomass production of seedlings were also obviously fluctuating,root nodule numbers 0.3~8.9/plant;seedlings heights -2.1-40.3 cm;diameters at ground level -0.01~0.18 cm;biomass above ground (stem,shoot and leaf) -0.205~5.072 g/plant;biomass under ground (roots and nodules) -0.009~1.324 g/plant;total biomass -0.101~6.396 g/plant.This indicated that nitrogen fixation capabilities of different genotypes provenances and families of Casuarina species are genetically variable.Finally,by the Multiple Objective Strategic Decision Analysis methods,24 Frankia-genotype associations were optimized and ordered,and some optimum associations were found out.