Abstract: Based on the model pipeline, in the determination of static yieldstrength value and the test of static wax concentration, it has been generally evaluated for those ranges of viscosity reduction, effectiveness of reducing yield-strength value and coefficient of wax prevention etc, by the way of adding F21 wax crystal improving agent into the Shengli crude oil. Thus, it has been shown that adding F21 has a good result both for the increasement of pipeline throughput in a specific condition and for the extension of pipeline shutdown time.