Based on the decline of A₆₃₀ with the clot lyses, the －A₆₃₀ of many samples was detected at the same time with EL311 Auto Reader. It was found that the A₆₃₀ declined linearly with time, and k under different dillutions could reflect the fibrinolytic activity of enzyme. This method costs less time, less reagent and correlated with CLT very well, indicating it was a good and useful method for determination of fibrinolytic enzymes.