Four constrained equations were established by vector method with complex numbers according to four loops of the mechanism and four supplement equations were also established by increasing four variables and the relation of sine and cosine function. The established eight equations are that of forward displacement analysis of the 30th 2-coupled–degree nine-link Barranov truss mechanism. Combining least square method with hyper-chaotic sequences, hyper-chaotic least square method based on utilizing two-dimensional discrete hyper-chaotic system to obtain locate initial points to find all real solutions of the nonlinear questions was proposed. The numerical example of forward displacement analysis was given. Comparison was also done with other finding solution method. The result shows that all real solutions have been quickly obtained, and it proves the correctness and validity of the proposed method.