Phosphorus-containing compounds belong to an important class of halogen free flame retardants that are environmentally friendly. Metal salts of phosphinates exhibit low moisture absorption and good electrical properties. The performance of polymers based on phosphinate salts depends on the structure of the salts as well as on the polymer itself. In this study, dialkylphosphinate salts (I) and amide-containing phosphinate salts(II) with varying metal cation and organic groups were prepared by using butyl methyphosphinate and 2-methy-2,5-dioxo-1,2-oxapho--spholane (OP) as raw material, separately. These phosphinates were used as flame retardants for epoxy resin(EP), poly(butylene terephthalate) (PBT) and poly (L-lactide)(PLA), the performance of the polymer. Their flame retardancy, mechanical properties, thermal stability, compatibility between phosphinate salts and polymer, and leaching of the salts from the polymer were investigated with respect to the structure of phosphinate salts and polymer being used. Results showed that the metal cation of the phosphinate salts influences the flame retardancy of the polymer and catalyze the decomposition of the polymer during heating, while the alkyl structure of the phosphinate salts have more influence on the compatibility between the salts and the polymer, on the mechanical properties as well as on the leaching of the salts from the polymer. In addition, dialkylphosphinate salts (I) show better flame-retardancy in EP than in PLA and PBT, while amide-containing phosphinate salts(II) show excellent flame-retardancy in PBT.