This paper presents a pilot test results of xanthan flooding in Shengli oil field, China. Emphasis is on the polymer flooding solution properties during the field test. The xanthan was considered as a desired polymer because it is shearing resistant and salinity durable. During the injection period, solution property was evaluated after injection pump, at the wellhead and the formation flow back. It is found that under uncontrolled shearing viscosity loss is unacceptable, which was not perceived and somewhat contradictory to early literatures. At first the xanthan was thought to be shearing resistant, therefore, one pump was used to inject the xanthan into four wells. The injection rate for individual well was adjusted by valves. Measurement showed that the solution viscosity behind the values can decrease as much as 40%. So the "one pump for one well" injection was used.