The invention discloses a preparation method of a shepherd's purse sausage. The preparation method comprises the following steps: S1, preparing the following raw materials in parts by weight: 35-45 parts of chicken, 0.7-1.2 parts of table salt, 0.2-0.5 part of phosphate, 0.0015-0.002 part of sodium nitrite, 12-18 parts of ice water, 15-20 parts of fatlining, 0.2-0.6 part of carrageenan, 0.1-0.2 part of spiceries, 0.8-1.5 parts of protein isolate, 8-13 parts of cassava starch, 8-15 parts of shepherd's purse, 3-4 parts of white granulated sugar, 0.05-0.1 part of ethyl maltol and 0.3-0.8 part ofmonosodium glutamate; S2, mincing the chicken and the fat lining for later use; S3, dissolving a pigment in the ice water, uniformly stirring the ice water with the minced chicken and fat lining, andadding the table salt, the phosphate and the sodium nitrite; S4, performing stirring in vacuum, and performing vacuum pumping until the vacuum degree is -6 to -8 MPa, wherein the stirring time is notless than 8 minutes; S5, taking the mixture out of the pot, backing with ice water and delivering into a high-temperature warehouse for pickling to obtain stuffing; S6, adding the spiceries, the residual ice water, the white granulated sugar, the carrageenan, ethyl maltol, monosodium glutamate, protein isolate and the shepherd's purse, performing uniform stirring, adding the cassava starch, maintaining the conditions under the vacuum degree of -6 to -8 MPa for 2-3 minutes and taking the material out of the pot; and S7, performing filling, drying, steaming, cooling and packaging processes.