The basic scientific, methodological and technological problems of program engineering which arise at various stages of life cycle of modern difficult complexes of programs are considered. In the first part problems of maintenance of quality of software products are presented, to safety of their application, reduction of risks of adverse events and economics in the course of creation, to operation and updating of program systems. Within the limits of these problems the most actual private problems are allocated and formulated and methods and ways of their decision are presented.