In this paper we introduce a new software, 'ECL-PACKAGE', for numerical simulation of electrogenerated chemifluminescence (ECL) at microelectrodes of various geometries: sphere, microdisc, channel double microband electrodes during non-steady state electrolysis. We employ numerical finite difference and finite element methods with co-ordinate transformations, which give accurate results near the electrode region. The package permits the user to optimise the conditions of ECL excitation (the ECL intensity and current), to predict and treat the experimental data by varying the geometric, physicochemical and simulating parameters in the programs.