Biodegradable poly(butanediol succinate-co-L-lactate) (PBSLA) copolyesters were modified using organic modified montmorillonite (OMMT) and Mica layered silicate inorganic fillers in solution blending method. The thermal properties, crystallization properties, barrier properties and mechanical properties of PBSLA/laminosilicate composites were studied. The results show that when the mass fraction of the layered silicate filler is less than 4%, its dispersion in copolyester matrix is good. The inorganic filler acts as the heterogeneous nucleating agent, which improves the crystallization property of the matrix material to some extent. In terms of mechanical properties, a certain amount of layered silicate filler plays an enhanced role. When the addition of OMMT and Mica is 2% and 3%, respectively, the tensile strength of the composites reache the maximum value, and can be increased by 18.4% and 34.4% compared with PBSLA, respectively. The layered structure effectively increases the zigzag path of gas molecules. With the increase of filler content, the water vapor and oxygen permeability coefficients of the composite show a downward trend. Therefore, the addition of layered silicate fillers can improve the barrier properties of PBSLA matrix materials.