In this paper, we present the function of the processing conditions (the amount of filler or diluent in epoxy resin, whether post-curing or not) in thermal properties of the modified silica/epoxy nano-composite materials based on thermal gravimetric analysis (TGA).The results is showed that after post-processing for the nanocomposite materials have a better thermal properties, and adding 3.2wt.% epoxy diluent can be taken a convenience operation, but has a negative effect on thermal properties. Nano-composite materials of diluent 3.2 wt.% plus nano-silica powder 2 wt.% will reach pyrolysis temperature 278.66°C. This reinforcement reaches the highest level observed of the decomposition temperatures of 2wt.% silica filler with no diluent cases nano-composite materials, after post-processing the decomposition temperatures could be enhanced to pyrolysis temperature 308.69 °C.