Based on the studies of simulated annealing algorithm, the continuous model space of the very fast simulated annealing was transformed to a variable discrete form in this paper. It can be proved by theoretical models that 5 to 10 times calculation work load can be saved. With a purpose to suit the needs of joint inversion, the ‘single judge’ error checking rule of the very fast simulated annealing algorithm was developed to the ‘double judge’ error checking rule to avoid the judge mistakes made by Metropolis accepting rule. Then, onedimensional and two-dimensional multi-parameters joint inversion of magnetotelluric and seismic data under the uneven topography conditions were put forward. Furthermore, the example calculation results of the theoretical models and real observed data illustrated that this constraint joint inversion technique was quite effective.