Abstract: Early detection is essential in the management of patients with cancer. PFK-nhibition test is a new method for detecting cancer in its early stage, and has been proved to e more sensitive than the prevailing screening test such as AFP or CEA. Sera from cancer atients specifically suppressed PFK. The PFK-inhibition rate（%） of 73 normal sera from ealthy ged （54-57 years old） with an average of 61.8 is 10.0±0.340 X±SEM); of 31 sera from benign iseases 54.2 years old in average is 26.6±0.598 （X±SEM）; of 52 sera from cancer patients averagely 62.0 years old) is 43.7±0.476 （X±SEM）. It is evident that the Value of serum rom ancer patient is significantly different from that in healthy subject or patient with benign iseases （P＜0.01）, These results suggest that PFK-inhibition test may serve as an useful arameter in the monitoring and early detection of cancer.