Determination of the performance characteristics of hemodialyzers newly developed is indispensable for assessing device design and the hemdialysis process. This study measured the solute clearances and ultrafiltration properties of the hollow fiber dialyzers developed in Taiwan according the international standard ISO 8637 : 2010. The test were performed on 3 dialyzers each from two model types( model-160 and 180) The solute clearances (K) of urea, creatinine, pbosphate and vitamin B12 were determined with dialysis fluid as test solution at 37℃ with blood and dialysate flow rates covering the manufacturer's specified ranges. The test solution used to measure the ultrafiltration coefficients (KUF) was heparinized pig's whole blood with a hematocrit of ( 32±3) % and a protein content of(60±5)g/L at 37℃. The sieving coefficients for albumin, inulin, β2-microglobulin were measured with test solution of heparinized pig's plasma with a protein content of (60±5)g/L at 37℃. All tests were run on a standard calibrated Fresenius 4008 hemodialysis machine. All data presented here are expressed as the mean ±SD (standard deviation ) .The mass transfer area coefficients (KoA) were included. The theoretical clearances at specified blood and dialysate flow rates were also discussed. The deviations of tbeoretical prediction of clearances from test results were all within 5%. All test results show that both two types of dialyzers are highly permeable and high-flux. They are equivalent to commercially available high permeable hemodialyzers. The two types of dialyzers may have the potential of clinical use.