Résumé : The characteristic functions of a row contractions are multi-analytic operators developed by Popescu. Characteristic functions are important in understanding the structure of a row contractions. Jaydeb Sarkar, Kalpesh Haria and A. Maji factorized the characteristic function of a row contraction using Julia-Halmos matrix. We will prove similar factorization for characteristic function of step lifting. Further, we prove that for a contractive step lifting consisting of two minimal liftings, the product of characteristic functions of these minimal liftings is the characteristic function of the minimal part of the step lifting. Finally, we consider an example
to verify the theorem.