Abstract: A technique for nonlinear analysis of space grids is presented. Modulus modification method is used to analyse the internal forces and node displacements of the grid structure in its post-elastic range, and a new numerical integration method to derive strut buckling behaviour. Considering factors such as complex strain-stress relations of structural materials, various types of cross-sectional shape of members, initial curvature and initial eccentricity of members, and partial elastic unloading of the sections of struts, this integration method extends the application range of nonlinear analysis, and improves the accuracy of the analysis.