A card insertion structure suited for a portable electronic device is provided. The portable electronic device includes a housing. The card insertion structure includes a base disposed in the housing, a pressing member movably disposed on the base, and a plastic spring strip disposed on the base. A portion of the pressing member is exposed out of the housing. The plastic spring strip leans against the pressing member and the base. A force supplied via an insertion of an electronic card drives the pressing member to deform the plastic spring strip, and after the electronic card passing by the pressing member and being inserted into the card insertion structure between the base and the housing, the pressing member is released and is restored by resilience of the plastic spring strip, and the electronic card is fixed with the housing by the pressing member.