Abstract: Back analysis of measured displacements has found application in rock engineering, structure detecting, biomechanical diagnosis, etc. The paper addresses the inverse formulation method and the direct formulation method for back analysis of measured displacements, and introduces two algorithmic programs based on the above two methods for identifying initial geostress parameters and rock modulus. Some distinctions of the two method, such as models of geostress, goal parameters, inverse algorithms, and so on, are analyzed and the constrained variable metric algorithm for solving nonlinear programming is highlighted. The methods and programs are applied in construction forecast of rock mechanics. Inverse results of different degree of rationality and precision are achieved, and optimum parameters in a interval are found.