In th is paper, a new business p rocess exp ression app roach forBPR has been p roposed. F irstly, the activity2attribute flow chart is used to describe p rocess. Secondly, the flow chart is analyzed by graph2 matrix analysis. Th irdly, a p rocess algebraic formula is draw n out from the matrixes. F inally, the perfor2 mance of business p rocess is evaluated th rough the analysis of p rocess algebraic formula. The evaluation of a p rocess is based on the performance p robability, the performance time of some p rocess routines, the ex2 pectative performance time of the activities in a p rocess, and the total expected performance time of the flow.