The microfluidic chip has been used as an example to discuss different mold insert materials by micro hot-embossing molding. For the mold insert, this study uses the SU-8 photoresist to coat on the silicon wafer, then uses UV light to expose the pattern on the surface of SU-8 photoresist, and coat the seed layer on the SU-8 structure using thermal evaporation. The micro electro-forming technology has been combined to fabricate the mold inserts (Ni, Ni-Co) followed by replicating the microstructure from the metal mold insert by micro-hot embossing molding. Different processing parameters (Embossing temperature, embossing pressure, embossing time, and demolding temperature) for the properties of COP film of microfluidic chip have been discussed. The results show that the most important parameter is the embossing temperature for replication properties of molded microfluidic chip. The demolding temperature is the most important parameter for surface roughness of the molded microfluidic chip. The Ni-Co mold insert is the most suitable mold material for molded microfluidic chip by microhot embossing molding. The bonding temperature is the most important factor for the bonding strength of sealed microfluidic chip by tensile bonding test. POLYM. ENG. SCI., 49:104-114, 2009. (C) 2008 Society of Plastics Engineers