In many industries, there are few nonlinear elements present in the system. Many industries used conventional controllers like P, PI and PID for controlling the controlled variable of the process. Controlling the nonlinear processes is a challenging task. In this paper conventional PI controller parameters are tuned using Fuzzy rules for maintaining the liquid level in the conical tank at desired level. Fuzzy rule base reasoning method used to determine a tuning parameter α based on the error and the rate of change of error of the process. This tuning parameter is used to calculate the Proportional gain and Integral gain of the PI Controller. Time domain analysis and performance indices are calculated and compared with Zeigler Nichols tuning method