3D-Ising Model as a String Theory in Three Dimentional Euclidean Space

A three dimensional string model is analyzed in the strong coupling regime. The contribution of surfaces with different topology to the partition function is essential. A set of corresponding models is discovered. Their critical indices, which depend on two integers (m,n), are calculated analyticaly. The critical indices of the three dimensioal Ising model should belong to this set. A possible connection with the chain of three dimensional lattice Pott's models is pointed out.