Elastin-like polypeptides (ELPs) are stimulus-responsive protein-based biopolymers, and some ELP block copolymers can assemble into spherical nanoparticles with thermosensitivity. In this study, three differently charged-neutral diblock ELPs with different ratios of (1:8, 1:4, and 1:2) and one neutral ELP were synthesized, and the dependence of their physical properties on ELP concentration, pH, temperature, and salt concentration was investigated. In deionized water, all ELPs showed one-step transition behavior from soluble single chains below the transition temperature (T_t), to macroscopic aggregates above the T_t. In NaCl solutions, while neutral ELP still aggregated above the T_t, the charged-neutral diblock ELPs (1:4 and 1:2) formed hydrophobic core micelles by self-assembly above certain NaCl concentration and would not aggregate due to the repulsive force between the same charged molecules on the surface. The temperature-triggered self-assembly behavior of each ELP as a function of block ratio, temperature, and salt concentration was investigated using analytical instruments that included a turbidimeter, dynamic light scattering, and transmission electron microscopy.