In this paper, engine simulation results are presented to give information on the effect of diesel-biodiesel blends on combustion and emission characteristics of a multiple injection automotive diesel engine. Numerical Study was performed in Computational Fluid Dynamics (CFD) simulation software AVL-FIRE coupled to AVL-ESE Diesel. An improved version of the ECFM-3Z combustion model has been applied coupled with advanced Zeldovich and Kinetic models for NO and soot formation, respectively. The simulation results were validated against the experimental results by comparing the in-cylinder pressure and heat release rate for diesel-biodiesel blends at 2000 rpm under 100% load, and a maximum variation of 5% deviation on the peak cylinder pressure and 4% for heat release rate was found. Simulation results revealed that with the increase of biodiesel amount in the fuel, CO and soot emissions were reduced while NO increased at the simulated operating conditions. In addition, in-cylinder NO and Soot mass fractions were found to be high at 20 and 10 CA ATDC, respectively.