NOVELTY - Bactrocera minax protein bait comprises (in %): brewer's yeast hydrolyzate (10-20); ammonium acetate (0.2-1); red sugar (5); orange juice (5); and water (remaining amount).    USE - Used as a Bactrocera minax protein bait.    ADVANTAGE - The protein bait has wide raw material sources; can be prepared by a simple process; is cost efficient; does not cause environmental pollution; can kill the male and female pests with the average trapping force of 61.11%, which is higher than the American torula yeast, and the sweet and sour wine yeast.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (i) preparing Bactrocera minax protein bait, comprising: (ia) preparing the brewer's yeast hydrolyzate by (a) inactivating comprising pasteurizing the active brewer's yeast mud at 65 degrees C, naturally cooling to room temperature, (b) filtering it by 80-mesh sieve, then by 100-mesh sieve, removing the impurities on the brewer's yeast mud, (c) heating and condensing comprising heating and boiling it on the magnetic stirrer for 2-5 hours, naturally cooling to room temperature, (d) enzyme processing the protein comprising adding distilled water to the condensed yeast solution, preparing into 40-50% of yeast solution substrate, adding 0.12-0.24 g of papain for enzyme processing, stirring uniformly, adjusting the pH to 6.5 plus minus 0.2 by sodium hydroxide and hydrochloric acid, where the temperature is 65 plus minus 2 degrees C, and carrying out enzyme processing for 6-24 hours, (e) after the reaction, rapidly heating for 15 minutes at 95 degrees C, terminating the reaction and obtaining the protein hydrolysate, (f) adding 0.1-0.3% of preservative potassium sorbate into the brewer's yeast hydrolysate, storing at 4 degrees C, and (iia) preparing the Bactrocera minax protein bait comprising mixing brewer's yeast hydrolyzate (10-20 wt.%), ammonium acetate (0.2-1 wt.%), red sugar (5 wt.%), orange juice (5 wt.%) and adding water to 100%, completely stirring and obtaining the Bactrocera minax protein bait; and (ii) using the Bactrocera minax protein bait by adopting trapping or spraying mode, comprising (iia) trapping by suspending the trapper in the orange garden from may to august, adding 50 ml of Bactrocera minax protein bait to each trapper, adding some low-toxin and low-residue pesticide e.g. dipterex, adding water to dilute to 300 ml, suspending the trapper in the shady side of the tree crown, whose height is 1.2-1.5 m, changing the protein bait each week, and (iib) spraying by diluting the protein bait, mixing it with the pesticide, spraying it on the back surface of the tree crown in late may, and middle of June and July, spraying one-third of the tree crown in each orange tree, and spraying one-third of the garden in each garden point.