1. A method for developing molecular mechanics force field parameters for computer simulations of molecular systems, which include molecules, clusters of molecules and clusters of atoms, comprising of the following steps: a) creating or importing molecular models that represent said molecular systems to be parameterized; b) searching a database for matches between said molecular models and stored molecular models and retrieving stored parameters if complete matches are found; c) preparing input data for quantum mechanics ab initio calculations for said molecular models; d) importing calculated data of said quantum mechanics ab initio calculations for said molecular models; e) selecting force field type and functional forms, and assigning atom types to said molecular models; f) estimating initial force field parameters for said molecular models based on said database or a set of mathematical formulas for said molecular models; g) optimizing said initial force field parameters to fit said input data of quantum mechanics ab initio calculations; h) validating the optimized force field parameters; and i) exporting said optimized force field parameters in required formats to external molecular mechanics simulation packages and saving the molecular models, input data and optimize force field parameters to said database;