A representation in the form of spectral parameter power series (SPPS) is given for a general solution of a one dimension Dirac system containing arbitrary matrix coefficient at the spectral parameter, where P , Q, R are 2 × 2 matrices whose entries are integrable complex-valued functions, P being invertible for every x, a transformation reducing it to a system ( * ) is shown.The general scheme of application of the SPPS representation to the solution of initial value and spectral problems as well as numerical illustrations are provided.