Flax fibres are oftenly used for reinforcing thermoplastic to manufacture biocomposite materials exhibiting numerous advantages such as high mechanical properties, low density and biodegradability. The mechanical properties of a biocomposite material depends on the nature and orientation of the fibres, the nature of the matrix and mainly on the adhesion between fiber and the polymer matrix. The main problem with these natural fiber is poor compatability and hydrophilic nature. Therefore, the fiber is needed to be chemically treated to reduce water absorption, enhancing adhesion between fiber and polymer matrix. For selecting most suitable thermoplastic polymer for a certain application, the properties of the available polymers is needed to known. Since data tend to be widely scattered over many sources, it is the purpose of this paper to give an overview of the most relevant properties of flax, thermoplastic polymers and various chemical treatment and processing techniques adopted for developing a range of thermoplastic biocomposite.