Objective To explore the influence of different biological sources of thromboplastin reagent on prothrombin time (PT) detection .Methods The thromboplastin reagents sourced from the rabbit brain extract provided by the Shanghai Taiyang Bi‐ological Technology Co .,Ltd .and Shanghai Changdao Biological Technology Co .,Ltd .and recombination tissue factor were selected and used for detecting PT in the non‐Warfarin treatment group(group A ,38 cases) and the Warfarin group(group B ,43 cases) by the Sysmex CA7000 blood coagulation analyzer .The detection results from different sources of prothrombin reagents were com‐pared between the two groups and performed the statistical analysis .Results In the group A ,the detection results had no statistical differences among the reagent R1 ,R2 ,R3 and R4 (F=3 .42 ,P>0 .05 ,n=38);in the group B ,the detection results had statistical differences among the reagent R1 ,R2 ,R3 and R4 (F=57 .68 ,P<0 .05 ,n=43) ,while the detection results had no statistical differ‐ences between reagent R1 and R3(t=2 .21 ,P>0 .05) and between reagent R2 and R4(t=2 .09 ,P>0 .05) .Conclusion The detec‐tion results of PT by different sources of PT reagent in the non‐Warfarin treatment patients demonstrate no significant difference , but the detection results in the Warfarin treatment patients have highly significant difference;the recombination tissue factor throm‐boplastin reagent has higher sensitivity ,which used for monitoring PT in the warfarin treated patients should establish a new thera‐peutic standard value for avoiding to cause the misdiagnosis and mistreatment .