Abstract：Objective To verify the precision, accuracy and linearity of Cobas C501 automatic biochemical analyzer by using total protein (TP) as a reference. Methods According to EP5-A2, EP6-A etc from Clinical and Laboratory Standards Institute (CLSI), TP was analyzed with Roche original reagent and calibrator to verify Cobas C501 automatic biochemical analyzer precision, accuracy and linearity. The EP evaluator software was applied for statistics analysis. Results In the 2 levels of TP, both of within standard deviation (SD) and total SD were less than verification value. The precision was acceptable. 20 specimens were measured by control instrument and experiment instrument; all of error indexes (EI) were in ±1.00 range. The accuracy verification passed. In linearity evaluation, the results of four of the five specimens over the reportable range were linear which indicating linearity was acceptable. Conclusion The precision, accuracy and linearity of TP detected by Cobas C501 system reach the performance that the manufacturer claimed．