Abstract: The important characteristic parameter , namely the effective enthalpies of ablation, was obtained by the research on CF/S-157PF composite under oxyacetylene flame test conditions. And using multiple linear regression, the mathematic model between the effective enthalpies of ablation, the two major factors, namely the heat flux density and ablation time is as follows:H_eff=0.016 3·q^{0.871 5}·t^{0.191 3} . Being verified, the regression model is very applicable and the forecast accuracy is much better.So the erosion properties of CF/S-157PF composite can be evaluated rapidly, effectively and accurately in the oxyacetylene flame test.

Key words: Composite, Flame, Enthalpy, Multiple regression, Mathematic model