Many PEO-PPO-PEO triblock copolymers (trade name Pluronics) form micelles at low concentrations like many low molecular weight surfactants. At higher concentrations, a gel region is found in a certain temperature range in many of these systems. Many studies have treated the structure of the gels and the mechanisms of their formation. In these systems, both body-centered cubic, face-centered cubic types of structures are documented. The thermal changes in degree of hydrophilicity of both PEO and PPO lead in these systems to temperature-induced order-order transition. Moreover, the stability region of the gel is markedly affected by the presence of cosolutes. In order to against dilution and low temperature, the micelles can be cross-linked either at the periphery of the corona or within the core to stabilized by a cross-linked semi-interpenetrating net-work (sIPN). In this study, we investigate the effects of homopolymers and sIPN on the micellization and gelation of Pluronics F127 triblock copolymer aqueous solutions. In the presence of homopolymers and sIPN, the sol-gel transition and gelation properties have significant difference between the pure Pluronics F127 aqueous solutions. Therefore rheological properties of these modified micellar systems were investigated in both linear and nonlinear regions under dynamic oscillatory shear flow. Especially, nonlinear rheological properties under large amplitude oscillatory shear (LAOS) flow are very sensitive to the generated microstructures (gelation structure). In order to analyze nonlinear stress curve, we compared the shape of stress curves, Lissajous pattern, and Fourier transform (FT) rheology. Gel strength for various micellar systems were also tested with uniaxial compression. Furthermore, microstructure of micelles and gels were investigated with Small Angle Neutron Scattering (SANS) test. From these investigations, it was found that homopolymers and sIPN have significant effect on micellization and g