The invention belongs to the field of functional food preparation, and specifically discloses a preparation method for a pasha worm extract with an immunity regulating function. The method comprises the following steps: step 1) cleaning fresh pasha worms with pure water, removing heads, tails and internal organs, cleaning and draining, and quickly freezing at a temperature of -80 DEG C for later use; 2) before extracting active ingredients, crushing into 5 mm small pieces after unfreezing at a constant temperature in warm water of 25 DEG C, freezing and drying for 36 hours in a freeze-drying machine, re-crushing until materials pass through a 40-mesh sieve, and sealing at the temperature of -20 DEG C for later use; 3) adding distilled water according to a solid-liquid ratio of 1 :2 to 1:4,soaking in warm water of 25 DEG C, using an ultrasonic drug processor to extract and filter, taking filtrate, and drying the filtrate on the freeze-drying machine to dry for 36 hours, and collectinga dried sample. The obtained pasha worm extract realizes immune protection on mice cells with low immunity; and pasha worm aqueous extract has obvious protection effect on special humoral immunity ofthe mice with low immunity.