Nowadays, most of the researches are focused on metal nanoparticles.They have unique properties on magnetic, electronic, optical and chemical behaviour compared to bulk materials, because of their large surface area to volume ratio. Transition metal nanoparticles have the high catalytic activities in organic reactions. But the soluble metal nanoparticles have some problems such as recycling and separation of these catalysts from reactions. To solve these problems it would be better to immobilize them on suitable support materials and use them as heterogeneous catalysts. Therefore, most of current research are focused on modification of different supports for immobilization of metal nanoparticles. inorganic solids such as silica, carbon, clay, zeolites and TiO 2 are widely used to carry metal nanoparticles. Palladium metal is used to catalyze the carbon-carbon coupling reactions, such as Heck, Sonogashira, Suzuki and Still coupling reactions. Although these reactions are usually catalyzed by soluble Pd, but to solve the problems facing the homogeneous catalysts, it would be proper to use them as a heterogeneous catalyst. Silica is a suitable support to immobilize metals because of its high surface area, inertness and its low cost. The central objective of this research is to carry out the Heck and Sonogashira reactions, using the heterogeneous catalyst. Thus, this projects aims to design a heterogenous catalyst based on the immobilization of Pd on silica. At first silica was modified by 3-aminopropyltrimethoxysilane and the SiO 2 -NH 2 was synthesised, then cyanuric chloride was added to the surface and SiO 2 -Cyanuric-Cl was synthesised. After that 1,2-ethanedithiol was added to the surface and SiO 2 -Cyanuric-SH was synthesised. In each step the surface was washed by ethanol. Then Pd was immobilized on the modified silica and SiO 2 -Cyanuric-SH-Pd was prepared. Different techniques such as FT-IR, CHNS, BET, ICP and TEM were used for the characterization of the catalyst. The catalytic performance was examined in Heck and Sonogashira reactions. At first the condition was optimized for the reactions. In Heck reaction, iodobenzene reacted with some vinyls such as: methyl acrylate, t-butyl acrylate, Styrene and methylvinylketone in 130 °C, 24 hours, DMF as a solvent and NaOAc as a base. The conversion was 100% for all vinyls except methylvinylketone and the selectivity for styren was 88:22(trans:cis). In Sonogashira reaction, iodobenzene reacted with phenylactylene in 80 °C, 24 hours, NMP:H 2 O (4:1) as a solvent and NaOAc as a base. In sonogashira reaction the conversion was 100% and the selectivity was 91%. The reactions and products were analyzed by GC and GC-MS. The reusability of the catalyst was tested in two reactions. Thiol groups were used to immobilize Pd silica and the high resuability shows that the thiol is a suitable ligand to immobilized Pd on surface.