Electroslag furnace system is a complex nonlinear process with multivariable coupling, time-delay and parameter change. Through large numbers of experimentation and analysis, the interrelation of meltrate, magnetic voltage adjusting and secondary voltage, melting current is established. A control medel and an intelligent control method are proposed and it includes multivariable decoupling strategy, fuzzy self-tuning of delay time and PID parameters self-tuning with particle swarm optimization. The industrial application shows that new method can overcome nonlinear and strong coupling and has high control accuracy, strong robustness and adaptability.