The project elaborates on a simulation program for creating structure of infinite impulse response (IIR) filter. The simulation program will simulate how to design the IIR filter from determination specification, calculation of filter coefficient, structure realization and calculation of wordlength effect. Program will calculate the filter coefficient from input specification and is represented by a fixed number of bit (quantization). The calculation of IIR filter coefficient uses the Pole Zero Placement method and the Impulse Invariant method. Filter coefficient that has been quantized is formed in the form of direct and cascade structures. From the structures, program calculates the finite wordlenght effect that consists of coefficient quantization errors. The simulation program for the creation of the structure IRR filter was implemented and tested to observe the filter performance. The filter performance is observed from the curve of response frequency representing the output of simulation program. It has been observed that the Pole Zero Placement method is the best method to design IIR filter. High sampling frequency increases the performance of the filter and limited number of quantization bit decreases the performance of the filter. Keywords: IIR, Filter Coefficient, Structure Realization