A dynamic wax deposition model for Jienuo crude oil was established through laboratory wax deposition experiments. With safe operations ensured, taking the sum of average daily power and pigging costs（average daily costs of pipeline operation） as the objective function, a pigging frequency model for unheated oil pipelines was developed. Based on the operation data of Linyi-Zhaozhaizi stations in Linyi-Puyang pipeline, the influence of outlet temperature, throughput and soil temperature on optimized pigging frequency were analyzed. The results show that the average daily costs of pipeline operation will be increased while the pigging frequency will be extended with decreasing of the outlet temperature. The average daily costs of pipeline operation will be increased while the pigging frequency will be shortened with rising of the throughput, and the average daily costs of pipeline operation will be decreased first and then increased while the pigging frequency will be extended with increasing of the soil temperature.