An actual multi-cycle complex process was simulated and analyzed on microcomputer by solving simultaneous equations

and a new algorithm

the modified Newtons method

was presented. The Newtons method was modified in three aspects: partly removing the coupling items in the Jacobi matrix to ensure its convergence; reducing the number of conditions of the Jacobi to make the variables vary in step with each other; and iterating enough times after each inversion of the Jacobi to reduce the total times of inversion. Simulation of 150 groups of data show that the algorithm proposed is simple and efficient.