This article reports a method of bacteria culture on the surface of dialytic-bags which can prevent macromolecules from penetrating in or out. Using this method the author cultured 8 strains of staphylococcus and from the external dialytic fluid samples of supernatant were collected and analyzed with SDS-PAGE. The result showed that the concentration of bacteria cultured with this surface method was about 10 times as high as that with usual method. The concentration of bacteria-produced protein in the supernatant was also high enouph to give a clear protein spectrum with the original sample without concentrating,and different supernatant from different species and/or strains gave different spectrum patterns. The reproducibility of the experiments with all strains of bacteria was very satisfying. The data indicate that this cultural method may be useful in analyzation of bacterial protein products and clinical identification of bacteria.