Abstract: Aimed at the existing correlations of CHF (critical heat flux) under the condition of uniform heating, such as Sudo93, Sudo96, Knoebel and W3 formulas, the non-uniform heating condition was considered, and the correlation of CHF was generalized to rectangular channel condition and revised by the method of length of boiling and F factor method. Aimed at the actual operating case of China Advanced Research Reactor (CARR), the revised calculation results were compared with the experimental values of CARR. The results show that the results of Sudo series formulas which are revised by F factor are in good agreement with the experimental values, so they can better predict the CHF phenomenon of CARR.