Objective To provide an optimal working process for crossmatching by full-automatic blood typing instrument.Methods Two workflows were applied to crossmatch test by full-automatic blood typing instrument.One was diluting red blood cells of donor samples to concentrate of 1%,the other was detecting directly the donor′s packed red blood cells.Compared consistency and processing time of the two different workflows.Results Cross match results of two workflows were consistent well(U=0,P>0.05).The average processing times before testing and undergoing testing were not significantly different(t=0.692,t=0.562,P>0.05),whereas the average processing times after testing and throughout testing were significantly different(t=146.485,t=67.053,P<0.05).Conclusion The workflow of diluting donor′s sample before testing saved processing time and better suits hospital having a large quantity of specimens.