Objective To explore the prediction and correction methods of postoperative intraocular pressure (IOP) after small incision lenticule extraction (SMILE). Methods In this retrospective and prospective study, 90 patients (180 eyes) who underwent SMILE in the ophthalmology department of our hospital from Dec. 2019 to Dec. 2021 were enrolled. From them, 30 eyes were selected randomly as validation set, and the remaining 150 eyes were included as training set. A prospective selection of 51 patients (102 eyes) who received SMILE from Jan. to Sep. 2022 was included as test set. Firstly, IOP of the training set was analyzed 3 d before surgery, 1 week, 1 month, 3 months and 6 months after surgery to determine the IOP-stable phase and the amount of change in IOP (ΔIOP). Then, preoperative algebraic sum of sphero-cylinder (SC), spherical diopter, diopter of cylinder, IOP, central corneal thickness (CCT), mean corneal curvature (Km, the mean of flat corneal curvature ［K1］ and steep corneal curvature ［K2］), anterior chamber depth (ACD), amount of change of each parameter in postoperative IOP stability (ΔCCT, ΔKm, ΔK1, ΔK2, and ΔACD), and individual factors were selected, and the factors associated with ΔIOP were subsequently incorporated into the regression models. Finally, formulas suited for prediction and correction of IOP after clinical SMILE were developed and validated for efficacy. Results The postoperative IOP was all decreased after SMILE. There were no significant differences among 1-week, 3-month or 6-month postoperative IOP, but the differences of IOP between 1 month and the rest of time periods were statistically significant (all P＜0.05). Factors were selected and the following best regression equation was established: ΔIOP＝0.459×IOP_preoperative (mmHg)－0.183×SC (D)－0.041×age (year)＋1.292×ΔACD (mm)－1.270 (adjusted R²＝0.533, P＜0.001). Preoperative IOP and SC were included only, the simplified equation was: ΔIOP＝0.496×IOP_preoperative (mmHg)－0.194×SC (D)－2.952 (adjusted R²＝0.498, P＜0.001). Predictive and adjusted formulas obtained through rounding and intercept correction were as follows: IOP_{postoperative} (predicted) (mmHg)＝0.5×IOP_preoperative (mmHg)＋0.2×SC (D)＋3, IOP_{postoperative} (corrected) (mmHg)＝ IOP_{postoperative} (mmHg)＋0.5×IOP_preoperative (mmHg)－0.2×SC (D)－3. After internal validation and external testing, the prediction performance of the simplified formulas was good. Conclusion The IOP tends to stabilize at 3 months after SMILE, and the ΔIOP is correlated with diopter. Postoperative IOP can be rapidly predicted and corrected using simplified formulas.