The invention relates to a preparation method for a lamiophlomis rotata extract. The preparation method comprises the following steps: 1, taking lamiophlomis rotata herb, adding water, conducting decoction and extraction, and conducting filtration or centrifugation, concentration and elution to collect an eluant B; 2, adding activated carbon into the eluant B obtained in the step 1, stirring under the boiling condition at 50 DEG C for 0.5-2 h, and conducting still standing precipitation, filtration or centrifugation to respectively obtain a liquid part A and a solid part for later use; 3, adding ethanol into the solid part obtained in the step 2, uniformly stirring under the boiling condition at 50 DEG C, and conducting still standing precipitation, filtration or centrifugation to obtain a liquid part B; 4, merging the liquid part A and the liquid part B, conducting filtration or centrifugation, collecting a filtrate or a centrifugate, and concentrating the filtrate or the centrifugate into thick paste of which the relative density at 60 DEG C is 1.25-1.30 so as to obtain the lamiophlomis rotata extract. The lamiophlomis rotata extract prepared through the method is high in effective constituent and low in pigment content. Besides, the invention further discloses pasty non-transparent toothpaste prepared from the lamiophlomis rotata extract.