A normal pressure MWPC for beam diagnostics at RIBLL2 has been developed, which has a sensitive area of 80 mm×80 mm and consists of three-layer wire planes. The anode plane is designed with a wider frame to reduce the discharge and without using protection wires. The detector has been tested with a 55Fe X-ray source and a 200 MeV/u 12C beam from CSRm. A position resolution better than 250 μm along the anode wires and a detection efficiency higher than 90% have been achieved.