The effects of substrate temperature and selenization temperature on the structure, composition, electrical and optical properties of Cu2SnSe3 films were studied systematically. Cu2SnSe3 films deposited at various substrate temperatures (303-573 K) by the flash evaporation method are found to be non-stoichiometric. To compensate the selenium deficiency and obtain a single-phase, an annealing Cu2SnSe3 films deposited at 573 K was performed in selenium atmosphere. Cu2SnSe3 films deposited at a substrate temperature of 573 K and then selenized at 673 K were single phase and polycrystalline exhibiting monoclinic structure. The films showed p-type conductivity with a direct band gap of 0.84 eV.