Ring knife demoulding device

The invention discloses a ring knife demoulding device which comprises a base and a power device fixedly installed on the base. The lower end of the base is provided with an opening penetrating through the base, and the output end of the power device is slidably installed in the opening. According to the ring knife demoulding device, the power device drives a telescoping mechanism to act to enable the output end of the telescoping mechanism to slide and stretch out in the length direction of the opening and eject and press a cement soil sample, and then the cement soil sample is ejected out from a ring knife; due to the fact that the cement soil sample is evenly stressed, the disturbance and damage problems cannot be generated in the demoulding process, and the advantages of being simple in structure, convenient to use and high in demoulding speed are achieved.