Aiming at the problems such as too fast the pigging speed, excessive liquid peak at the outlet of the pipeline, increased energy consumption caused by increased gas input volume, etc. during the pigging of long-distance wet gas pipelines, a pigging model of long-distance wet gas pipeline is established based on OLGA software, and the influence of different gas input volume on the inlet pressure and liquid accumulation volume of hydraulic pigging pipeline is studied, and the variation rules of inlet pressure, pigging speed and liquid accumulation at the outlet of the pipeline during pig pigging operation is also studied. The results show that: for hydraulic pigging, the more the gas input volume, the lower the liquid accumulation volume in the pipeline, but it is not obvious when the gas input volume reaches certain range; for pig pigging, the more the gas input volume, the lower the inlet pressure vibration is, the higher the average velocity of the pig is, and the smaller the peak value of the instantaneous liquid volume at the outlet of the pipeline is. The pigging transient simulation is carried out for a gas field. The results show that the pigging effect is the best when the gas input volume is increased from 2.0×105 m3 to 2.8×105 m3 during hydraulic pigging and reduced to 4.2×105 m3 during pig pigging.