Abstract: Pseudo emulsion is a new flow phenomenon formed in the process of oil production and accumulation when flow improver is added into water cut oil. Pseudo emulsion flow is different from conventional oil, gas, and water mixture flow, and it can slow down the pipe flow greatly along on way resistance and local resistance, so that enhance oil pumping efficiency. Local resistance coefficient of water cut oil in the plunger is an important parameter to design and calculate in actual production. This article uses the dimension analytic method to solve local resitance coeffient of pseudo emulsion in plunger, and compares this coefficient with the actual value. It is proved the dimensional analytical method has certain project application value.