Abstract: Detemination of partially hydrolyzed polyacrylamide(PHPA)in chemical flooding systems with three pore diameter macroporous silica based diol phases is described. The diol phases SI-500,SI-1000,SI-3000 of pore size 50,100 and 300nm,respectively, are self synthesized in our laboratory.The mobile phases are 0.2mol/L or 0.5mol/0.5mol/L NaH₂PO₄and synthesized in our laboratory.The mobile phases are 0.2mol/L or 0.5mol/L NaH₂PO₄ and the detection is made at UV 210nm.The applications of rapidly quantitative determination of partially hydrolzed polyacrylamide(PHPA)in chemical flooding systems on different pore diameter macroporous silica diol stationary phases are described.The minimum detection concentration is found as 4mg/L and the recovery lies between 92% to 108%.Among three diol phases SI-500(pore she of 50nm)is the one to give the best resolution.A sample analysis can be achieved within 3 minutes.All additives in surfactant/polymer flooding systems show no interference.This method of determining PHPA is shown to bevery rapid and operative.