Thermoplastic composites were prepared using poly(vinylidene fluoride) (PVDF) having piezoelectric property and low density polyethylene (LDPE). The PVDF/LDPE island-in-a-sea fibers were prepared by melt conjugate spinning for ease of manufacture of the PVDF/LDPE thermoplastic composites. The PVDF and the LDPE were island component and sea component, respectively. And the PVDF/LDPE thermoplastic composites were manufactured through the compression molding under temperatures between melting temperatures of the PVDF and the LDPE. Through this process, the PVDF and the LDPE became a reinforcing fiber and a matrix of the thermoplastic composite, respectively. Composites were prepared under a various molding conditions. Manufactured composites have undergone a post-treatment process, such as poling and drawing for increase of beta-phase crystalline contents of PVDF. Through this process, piezoelectric properties were developed. Prepared PVDF/LDPE island-in-a-sea fiber and PVDF/LDPE thermoplastic composites were characterized. Morphologies of the PVDF/LDPE island-in-a-sea fiber and the PVDF/LDPE thermoplastic composites were analyzed using scanning electron microscopy (SEM). Universal testing machine (UTM) was used to measure the mechanical properties. Fourier transform infrared spectroscopy (FT-IR) was used to determine the crystalline characteristics. Finally, molding temperature of 110 A degrees C and molding time of 30 s were identified as an optimal condition for molding process of the PVDF/LDPE composite.