The particle swarm optimisation (PSO) for shape reconstruction of perfect conducting cylinder (PEC) buried in a half-space is presented. Assume that a conducting cylinder of unknown shape is buried in one half-space and scatters the field incident from another half-space where the scattered filed is measured. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations is derived and the imaging problem is reformulated into an optimisation problem. The inverse problem is resolved by an optimisation approach, and the global searching scheme PSO is then employed to search the parameter space. Numerical results demonstrate that even when the initial guess is far away from the exact one, good reconstruction can be obtained by using PSO both with and without the additive Gaussian noise.