On chip PCR is a hot area since the inherent advantages of microchip.In order to get higher PCR efficiency,surface modification is critical.In this paper,we used two new passivation agents,PLL-g-PEG and PLL-g-PMOXA,to modify the internal surface of microchips based on silicon oxide and PDMS which are two most widely used chip materials.Compared with PEG and PMOXA,PLL-g-PEG and PLL-g-PMOXA gave higher PCR efficiency in both silicon oxide and PDMS chip.The PCR yield in the microchip was triple of that in a traditional PCR tube.