Abstract: Aiming at the problems that change of emulsion liquid level of fully mechanized coal face had nonlinear and time-delay,its mathematical model was difficult to be established and so on,the paper introduced design of a control system of emulsion liquid level based on fuzzy-PID control.The system combines fuzzy control with traditional PID control.When difference of practical measurement liquid level and setting liquid level is bigger,the system adopts fuzzy control and when the difference is smaller,it adopts PID control.The control way is flexible and has good robust performance and strong anti-interference ability.The result of Matlab/Simulink simulation showed the system has fast response and high precision,which can meet control requirements of emulsion liquid level of fully mechanized coal face.