Abstract: The plastic parameters of materials were extracted from the loading part of load-depth curves obtained by coupling single indentation test and finite element simulation, and combining inverse method and simulated annealing particle swarm optimization. The strength of different metal materials was estimated on the basis of Ludwig hardening model and compared with the results obtained by uniaxial tensile test. The results show that the load-depth curves obtained by simulation almost coincided with those obtained by tests, and the relative error was less than 0.5%, indicating that plastic parameters could be extracted from indentation load-depth curves by simulated annealing particle swarm optimization. The true stress-true plastic strain curves extracted from indentation load-depth curves by inverse method based on Ludwig hardening model were not unique, but obvious convergence tendency of the strength estimated from the extracted true stress-true plastic strain could be observed. The strength of different metal materials obtained by the indentation tests was close to that obtained by tensile tests; the biggest relative errors of the yield strength and tensile strength were 5.9% and 4.3%, respectively, indicating that the strength of the metal materials could be evaluated accurately by indentation test method.