The invention discloses a design method for a freezing scheme of deep thick alluvium. The design method comprises the following steps of (a) drawing up a preliminary freezing construction plan according to a geological condition of the freezing construction strata; (b) calculating the design thickness of a frozen wall of the deep thick alluvium; (c) layout designing freezing holes of the deep thick alluvium; and (d) and according to the design thickness of the freezing wall of the deep thick alluvium calculated in step (b) and a layout scheme of the freezing holes of deep thick alluvium obtained in step (c), optimizing the preliminary freezing construction plan drew up in step (a) to obtain final freezing construction scheme. The design method provides technical guidance for designing thefreezing scheme required for freezing construction of the alluvium with a buried depth of over 600m, and thus lays a foundation for safety of freezing engineering of the deep thick alluvium, improvement of freezing efficiency and creation of a good digging and laying condition.