In this paper, a linear multi-regression model was used to study the degree of influence of various operating conditions on the permeation flux of deionized water and bovine serum albumin (BSA) solutions in the ranges of 0.04-0.16 MPa and 20-30 degrees C during dead-end microfiltration. In the experiment, two kinds of membrane were used. One was a PVDF membrane with pore size of 0.1 mu m, and the other was a PTFE membrane with a pore size of 0.2 mu m. Experimental and analytical results showed that temperature, pressure and concentration had a significant influence on the microfiltration membrane flux. For deionized water, the flux increased with increasing temperature and pressure, and the relative degree of influence of temperature and pressure on the microfiltration membrane flu K was different, 2% and 98%, respectively. The relationship was J(w) = -6.57 + 0.27 T+ 133.27 P. For BSA solutions, the flux increased with increasing temperature and pressure, while decreased with increasing concentration. The degree of influence of pressure, temperature and concentration on the permeation flux was 69%, 18%, 13%, respectively, and the relationship was J = -1.28 + 0.22 T + 33.11 P - 1.04 C. Therefore the relative importance of pressure on the membrane flux was much greater than that of temperature or concentration.