In order to study the creep mechanical characteristics of soft soil under the improvement design of the Helei pump station project site, a triaxial confining pressure unloading creep test was designed, and the influence of improved design parameters and soil moisture content on creep mechanical effects was analyzed. The research shows that controlling the dosage of modifiers can help slow down the onset time of creep and also control the level of creep strain.Conducting pressure recovery tests can not only delay the accelerated creep of improved soil, but also delay the unloading period of confining pressure. The longer the pressure recovery time, the lower the creep strain level of the sample. When the moisture content of the improved soil sample is higher, the sample will experience accelerated creep in advance, and the duration of deceleration creep in the early stage of confining pressure unloading will be longer, and the steady-state creep rate will also be higher. The paper has certain reference value for the improvement design of soft soil in related engineering and the experimental study of creep mechanics under confining pressure unloading.