Abstract: Objective Using computer image-analyze technique(CIAT)to study changes of geometry pa-rameters in human spleen nuclei and seek a new experimental method to deduce the estimation the post-mortem interval(PMI).Methods31cadavers that known accurate PMI,sampled and smeared respectively every hour within the first36hours after death,fixed with cold Carony fixation,stained by Feulgen-van's method,and measured5geometry parameters using the image-analyze instrument including Area(A),Mean-Dia(MD),Average Diameter(AD),perimeter(P),Index of density(ID).Results A,MD,AD and P in the human spleen nuclei have no correlation with the PMI.But ID rose regularly with the prolongation of PMI in36hours.There was a definite correlation between ID and the PMI,r=0.983,linear regression equation with PMI(hours)as the dependent variable was calculated for ID.Conclusion Geometry parame-ter ID was proved to be preferable indexes for estimation of PMI in36hours.

Key words: forensic pathology, postmortem interval, DNA degradation, image analysis