The traditional trajectory fitting method always needs a priori enactment about the structure form of the fitting equation and is not adaptable when it is used to fit trajectory under the large range launching condition.In view of these deficiencies, a bomb trajectory fitting method based on group genetic programming (GGP) is proposed.First, the GGP model samples data of different launching conditions are obtained through bomb dynamics simulation. Then, on the basis of mapping inputoutput training of these trajectory data and initial launching value by the GGP, multiple trajectory fitting equations are provided. The accuracy between ungroup and group equations is compared based on modeling errors as well as generalization ability for untrained samples. A lot of checking calculation shows that the GGP method has clear physical relations, a high precision, good generalization and can fast calculate.