Abstract: The functional characteristics of native fish protein can be changed under conditions of extrusion cooking, depending upon the operational variables used. A Clextral BC-45 laboratory-scale twin-screw extruder was used together with response surface methodology to study the effect of process parameters on functional properties of textured fish protein, Parameters examined were： barrel temperature in the last zone, screw speed, teed moisture; each at 5 levels. Water holding capacity and texture profile assessments of the resultant extmdates were made, Results had shown that all of three operational variables did not affect wet extrusion cooking in the same way. Polynomial regression equations of process variables with two functional properties were obtained with R^2 = 1.000, and R^2 = 0.933, respectively. Both of regression equations are hightly credible.