A compact electrophoretic system has specially been designed and established (Figure 1) to conduct fast and highly efficient size separation of protein mixtures by homogeneous sodium dodecyl sulphate capillary polyacrylamide gel electrophoresis (SDS-CPAGE).The key of the new method lies in the sample introduction which has much less discussed in respect of resolution efficiency.By exploration of surface tension, a picoliter-scaled sample introduction approach is developed from a free solution capillary electrophoresis [1] for SDS-CPAGE.To validate, a mixture of 6 FITC-labeled proteins was used as a testing sample and separated through only a 6 mm effective length in less than 40s with good reproducibility (RSD≤3%, Figure 2) and high efficiency (plate high < 0.6μm for BSA).The separation looks quite acceptable.