Abstract: The dimension criterion of state space is proposed from the first principles of chemical process．Independent component analysis is believed as a method which analysis process state space and gain state variables．Some factors for state space determination are also discussed．In a simulation case‚the state space dimension and the state variables have been determined on the criterion．The multivariate statistics analysis consistent to the criterion determination；the state independent component direct-viewing and effectively describe the process system and independent component analysis is proved as an effective state space analysis method．

Key words: chemical process, state space, principle component analysis （PCA）, independent component analysis （ICA）, dimensional analysis, dimension