A novel polymethylmethacrylate（PMMA）/polydimethylsiloxane（PDMS）hybrid polymer microfluidic chip is reported.The chip has 4-layer structure of PMMA-PDMS…PDMS-PMMA to integrate the pneumatic microvalves.The fluid PMMA substrate and control PMMA substrate are irreversibly bonded to an elastic PDMS membrane to respectively form the fluid half chip and control half chip.Relying on the adhering property of the PDMS membranes

the fluid and control halves are reversibly bonded to form a complete chip with micro valves.This method solves the bonding problems occurred in fabricating PMMA-PDMS-PMMA 3-layer microfluidic chip and the bonding process is simple and reliable.The control half and fluid half are allowed to be replaced individually

so the operation cost can be further reduced

which makes this microfluidic chip especially suitable for disposable use.The preliminary experiment results show that the microvalve has excellent switching performance and durability.