Abstract: In order to study the physical characteristics of high power beam in front of target, the European spallation neutron source plans to develop two beam diagnostic prototypes, including a multi-wire beam profile monitor and a beam halo monitor. Online testing of the prototypes will be conducted on the 3 GeV proton beam transmission line (3NBT) at J-PARC of Japan. In view of the small installation pipe on dump of 3NBT, and the drive mechanism of the prototype should have a large stroke, a multi-wire beam profile monitor of multipoint position suitable for small pipe is proposed, which is integrated with beam halo probe in one prototype. The prototype has compact structure and can realize independent drive of two monitors. The deformation of the monitors and their transmission rods has been analyzed by using ANSYS Workbench. The development of the prototype is completed. To ensure the reliability of the prototype, the off-line testing, such as optical image measurement of wire spacing, vacuum leak detecting, small aperture pass testing and on-off testing has been completed.