We report a simultaneous study in self-seeding and isothermal crystallization of polyethylene (PE) in the solution using time resolved small angle neutron scattering (SANS). We observe that the SANS spectra obtained from self-seeding technique are significantly different from isothermal crystallization technique of PE crystallization in solution. The first correlation peak from structure factor for self-seeding crystallization is not clear compare to isothermal crystallization spectra, indicating that crystals are dominantly in single or few lamellae forms. Structural information, such as the lamellar long period, lamellar crystal thickness, amorphous layers between lamellae, invariant and crystallinity has been quantitatively determined based on model fitting. Avrami analysis depicts 2D lamellar structure formation. (C) 2015 Elsevier Ltd. All rights reserved.