Similarly to earlier models for quantum error correcting codes, we introduce a quantuminformation theoretical model for quantum secret sharing schemes. This model providesnew insights into the theory of quantum secret sharing. By using our model, among otherresults, we give a shorter proof of Gottesman's theorem that the size of the shares in aquantum secret sharing scheme must be as large as the secret itself. Also, we introducedapproximate quantum secret sharing schemes and showed robustness of quantum secretsharing schemes by extending Gottesman's theorem to the approximate case.