With mimicking the injury model from murine peritoneal macrophages attacked by oxidized low density lipoprotein (OLDL), the time-de pendant and concentration-depandant effect of polysac charide K (PSK) on the foam-like change and attenuation of murine peritoneal macrophages attacked by OLDL was observed.After incubated with 10,50 and 100 mg·L-1 OLDL for 24,48,72 hOurs in vitro, the fingure of PSK-treated macrophages was maintained normal relatively.Moreover,in PSK-treated group, the amount of survival cells were higher with counted by MTT colorimetric analysis at every time points.So PSK could inhibit the foam-like change of macrophages efficiently.And after the change in macrophages formed,PSK could prolong the survival time of these macrophages.