Abstract: Polyethyleneimine-bovine serum albumin composite membranes were successfully prepared based on layer-by-layer self-assembly technology.The process of the self-assembly technology was examined by UV-Vis spectrophotometry.Mass concentration of bovine serum albumin solution found was 0.1 g·L-1 and concentration of polyethyleneimine solution found was 10 mmol·L-1,respectively.Soaking time of quartz substrate in the two solutions was 5 min,followed by washing 3 times with water (each time 1 min).Absorbance of the multilayer membranes increased with the number of adsorbed layers in a linear relationship,indicating the assembly of the composite membranes was uniform.The assembly process also had good reproducibility.The formation method of the composite membranes opened the possibility for usage in the preparation of enzyme biosensor.