The glass forming ability (GFA) is a problem of great concern in the research of amorphous materials. It is of great significance to understand the physical mechanism of GFA and to seek conditions and methods to improve it. In this study, we collected 820 experimental data from existing literature, and used gradient boosted decision trees (GBDT) model to predict the GFA. The GBDT model optimized by 10-fold cross-validation and grid search technology shows excellent predictive results. The determination coefficient (R2) and root mean square error (RMSE) are 0.652 and 2.85, respectively. Compared with the previously reported 27 criteria and ML models, GBDT model has the highest prediction ability. The result exhibit that the predictive performance of GBDT can be significantly improved by considering the atomic size difference, total electronegativity, mixing entropy and average atomic volume. •The GBDT model for predicting the GFA of amorphous alloys was developed.•Grid-search and cross-validation were used to determine the hyperparameters.•The GBDT model provides the highest accuracy in GFA prediction.•The predictive performance of GFA can be significantly improved after adding TEN, δ, VA and Sm.