This paper aimed at comprehensive utilization of rapeseed meal. The techniques of extraction and purification of rapeseed protein from double-low rapeseed meal deoiled by pressing at low temperature were investigated. Through pH value adjustment, orthogonal experiment, tests of extraction times and purification, preferable technical parameters on rapeseed protein extraction were achieved. The meal was extracted for 3 times, 20 min each time, at room temperature in an alkali solution with pH value 12 adjusted beforehand, and the extract was precipitated successively twice at pH value 5 and pH value 7, and then dried. The isolated rapeseed protein prepared under this condition was in a purity of 84.8%, a yield of 38.9%, and contained less deleterious compositions. The total extraction ratio of rapeseed protein by the method of pH value adjusted beforehand was above 90%, which was 20% higher than that by pH value adjusted afterward.