The interior conformations and elastic behaviors of protein-like lattice polymers in the process of tensile elongation are investigated by means of Monte Carlo method and the (310) hybrid lattice model. Here (HHPPHPP)(x) sequence of protein-like polymer chains is adopted. It is found that three types of contacts, i.e. HH-, PP- and HP-contact, have different behavior in the process of elongation. Second structures of protein-like chains, i.e. helical, coil and expanded structures, have distinct characteristic in our simulation. The average energy, the Helmholtz free energy and elastic force are also investigated at different temperature. Moreover, and as a function of elongation ratio carefully reflect the shape change in the process of tensile elongation, and the snapshots of contact maps can directly explain the interior conformation change of protein-like chains, therefore, here we give some discussions about the shape and the snapshots of contact maps. These investigations may provide some insights into the elastic behavior of protein-like chains. (C) 2004 Elsevier Ltd. All rights reserved.