The problem of debris left by the plant used melamine in the industrial sector, which contributes to the cost of debris removal and the removal of these also pollutes the environment. This project aims to study the mechanical properties of polymer composites between LDPE and melamine powder, a substance used LDPE and debris using melamine as a reinforce. The study will consider the factors of influence of particle size and filling ratio of melamine on the mechanical properties of composite materials. The mechanical properties test in this study are divided into tensile test ,impact test ,hardness test and bending test to bring the property to be used for decision to use composite materials in the manufacturing else.