Abstract: The authors have studied the water-drive behavior of L pool in the Laojunmiao oil field, based on the principles pertaining to oil and water flow and in reference to the method of studying displacement curver used by petroleum engineers Tong Xianzhang, Chen Yuanqian, etc. The importance and necessity of intensifying water injection is stressed for an oil field like Laojunmiao with such a long history. Their research indicates that linear relationship exists not only between such variables as W_p, WOR, F_w and N_p, R_o, S_w, but also between and F_w. Formulas have been worked out showing the relationship of factors influencing the water drive production of L pool that may be used for predicting reservoir performance. Feasibility of this method is established by a comparative study.