Abstract: With 60 rate as our samples,we studied the stainning changes of acid phosphateas in cerebral cortex at different time after injury.The amount of the enzyme at the injury zone was detected by means of Graphical Quantitative Analyzer.We found out that from 12 hours after injury to 5 days,the enzyme amount at the periphery of the injury zone showed lincal ascend ing with time index,from 3 days to 3 weeks the enzyme amount both at the periphery and the center of the injury zone showed lin- eal descending with time index.The lineal correlation is quite dis- tinct.With the lineal regressive equation made out from our ex- periment,we can accurately estimate the surviving time after brain injury.