An alginate impression method for dental treatment is provided. The method comprises steps of: separating a first portion and a second portion in a squeezable pouch with a separator; providing alginate in the first portion; providing water in the second portion; breaking the separator by squeezing the squeezable pouch; kneading the squeezable pouch so as to mix the alginate and the water inside; and squeezing out the mixed alginate and water onto a mold so as to make an impression. The squeezable pouch comprises a container portion, an opening, and a lid. The lid is configured to fit air-tightly with the opening of the squeezable pouch. The opening of the squeezable pouch comprises male threads inside the opening, and the lid of the pouch comprises female threads fitting with the male threads in the opening.