The invention discloses a fine pressure control well cementing operation method. The method comprises the following steps of preparing a wellhead sealing device matched with the outer diameter of a tubular column which is put down; conducting optimizing design on fine pressure control well cementing construction parameters through conventional well cementing software; according to fine pressure control well cementing design, putting a well cementing pipe string with pressure to a designed well depth, starting a pump for circular exhaust, and adjusting the density of drilling fluid of a well shaft to a designed value; after the density of the drilling fluid of the well shaft is stable, shutting down the pump, supplying pressure at a wellhead through fine pressure control ground equipment toguarantee the stability of the pressure under the well, and connecting well cementing construction equipment; pumping pre-pad fluid, cement paste, post-pad fluid and drilling fluid according to the fine pressure control well cementing construction design, after the liquid is pumped, the fine pressure control ground equipment gets involved, the under-well pressure reduction value caused by pump stopping is compensated for, and the stability of the pressure under the well is guaranteed; pressure continues to be supplied to the wellhead until cement is set, and then the pressure is relieved. Bymeans of the method, the complicated problem that spraying missing is caused by pressure fluctuation under the well in the construction process of the strata can be effectively solved, and the well cementing quality of the deep well is greatly improved.