Objective To evaluate the self‐developed device for transmitting negative pressure with large capacity before propa‐gating .Methods Totally 67 ribonucleic acid(RNA) of WBC > 2 .0 × 109 /L fresh whole blood were extracted with the intrinsic de‐vice(control) and the self‐developed device for transmitting negative pressure with large capacity(test) in parallel .The difference of the performance including efficiency ,concentration ,purity and integrity of RNA extraction were evaluated between the two groups . Results In 67 specimens of RNA extraction ,efficiency ,concentration ,purity and integrity of the control device were 0 .97(portion/minute) ,(248 .8 ± 21 .4)μg/mL ,(1 .995 ± 0 .095) (OD260/OD280) ,(2 .020 ± 0 .082) (OD260/OD230) ,1 .964 - 2 .025 (95% con‐fidence interval for mean) (OD260/OD280) ,2 .001 - 2 .040 (95% confidence interval for mean) (OD260/OD230) and complete . Those of test device were 1 .63 portion/minutes ,(260 .3 ± 21 .8)μg/mL ,(2 .093 ± 0 .092) at OD260/OD280 ,(2 .071 ± 0 .120) at OD260/OD230 ,2 .075 - 2 .113 for 95% confidence interval for mean at OD260/OD280 ,2 .044 - 2 .103 for 95% confidence interval for mean at OD260/OD230 and complete .The t value was 24 .570 (P< 0 .001) in paired t‐test ,and the linear regression equation was Y = 0 .950X + 0 .039 ,R2 = 0 .903 for the two groups data of RNA concentration .Conclusion The self‐developed device for transmitting negative pressure with large capacity is excellent in the work efficiency ,concentration ,purity ,integrality and of the RNA in extracting .It is better than the intrinsic device in the clinical value for situation of lab .