Aim To study the protective effect of polysaccharidesulfate on cell apoptosis in focal cerebral Ischemia-Reperfusion injury rats.Methods Right middle cerebral artery was occlude by inserting a thread through internal carotid artery for 1 h and 30 min,and then reperfused for 24 h. PSS were injected via intraperitoneal of the rats at 30 minutes before or 5 hours after reperfusion.Intra-cellular free calcium([Ca²⁺]i) and rates of apoptosis an1d death were measured by flow cytometry.The behavior of rats was investigated at the same time.Results The damage of rat's behavior in the PSS-treatment groups was small in comparison with untreated group.The numbers of apoptosis cells were dramatically reduced in the PSS-treatment groups in comparison with untreated group.While the increasing [Ca²⁺]i was reduced by PSS.These significant difference between 30 min before onset and 5 h after reperfusion groups was also discovered.Conclusions PSS reduced the neuronal damage and inhibited apoptosis induced by ischemia-reperfusion.The anti-apoptosis effects of it might be attributed to its effects by bating the increasing of [Ca²⁺]i.