Abstract: Based on the theory of classical mathematics and mechanics, this paper presented the semi analytical numerical method for the interaction problem of multiple connected region. A semi analytical displacement function was constructed in the radial and circular directions on the cross section of double tube tunnels. Three dimensional interaction problem of parallel tunnels construction was turned out to be one dimensional numerical problem. The result of the numerical test indicates that the semi analytical method with the displacement function presented here is reliable and efficient to the analysis and design for underground structures.