Zero dimensional engine modeling plays a vital role for spark assisted engine simulation to predict combustion, performance and emissions. Wiebe function either single or multi plot function predicted fuel mass fraction burned (mfb) during combustion as a function of crank angle variation more accurately compared to all other methods. The zero-D model shows its advantage by prediction accuracy and the less computational time. This work focused on comparative study of an experimental results and modeling study carried out to compare the performance of the single wiebe with multi-wiebe functions using Zero-D single zone engine model developed for the pure methane gas, pure hydrogen (H2) gas and blends of methane and hydrogen (30HCNG) fueled SI engine to predict mass burn fraction. The predicted results included mass burn fraction and in-cylinder pressure variation were validated using experimental results. For this a single-cylinder naturally aspirated (NA), water-cooled engine adapted to be operated at 1500 rpm using port fuel injection (PFI) of 30HCNG. It was observed that multi-wiebe function based model predicted more accurate compared to single wiebe function which tend to over predicted combustion pressure because of slower combustion at early combustion phase. The best agreement with predicted and experimental results were obtained by multi-wiebe function approach due to concise parameter which is governed by the center point of the combustion process and appropriate form factor.