The mixing scheme of biomass constituents, including cellulose, hemicellulose and lignin, was designed by using simplex-lattice mixture design (SLMD) method. The pyrolysis characteristics of biomass constituents were observed by using a thermo-gravimetric analyzer and the kinetic parameters were calculated. In addition, a prediction model for kinetic parameters was established and the model was verified by test. The results showed that the reaction order n, activation energy E and frequency factor A of cellulose were 1.20, 134.50kJ/mol and 3.49×1012s-1, respectively. Pyrolysis of cellulose was much rapider and more violent than the other two components. The value of n, E.and A for hemicellulose were 1.30, 33.51kJ/mol and 9.43×103s-1 and that for lignin were 1.32, 19.98kJ/mol and 107s-1. Pyrolysis of hemicellulose and lignin were relatively slow. Furthermore, three components in the mixed pyrolysis had interaction effect. Effects on the activation energy and the frequency factor of cellulose were significant while effect on the reaction order of hemicellulose and lignin was remarkable. The kinetic model is precision and it can effectively predict the biomass pyrolysis kinetic parameters.