In this work, two zone thermodynamic models have been developed for prediction of particulate matter (PM) from direct injection Diesel engine. Two key compositions of PM were considered in this simulation model developed, it consists of soot and soluble organic fraction (SOF). Soot formation model were developed initially and then coupled with SOF model to get overall PM formation rates. Primary soot formation rate was obtained by using Hirosysu model and Nagle and Strick-land-Constable model was adopted to get soot oxidation rate. The oxidation and formation rate difference gives overall soot formation value. Unburned hydrocarbons were considered as key factor for SOF formation so the formation and oxidation rate of hydrocarbon was determined. Then the difference between these two gives overall SOF formation rate. At last soot formation and SOF model was integrated to get overall PM formation rate. Various submodels like ignition delay, heat release rate, and combustion model were involved in this study to predict PM formation rate. Validation of this simulation model developed were carried out on single cylinder, naturally aspirated water cooled direct injection Diesel engine. Simulation results matched well with the experimental results and it clearly shows that model developed is an accurate one. Results obtained shows that soot formation increases at higher loads and SOF formation rate increase at lower loads. Simulation model developed is very useful for understanding the PM formation mechanisms and also useful for control of PM formation.