The RF linac dedicated to boron neutron capture therapy (BNCT02) in our institute is mainly composed of an ion source, a low energy beam transport line, a radio frequency quadrupole accelerator and three high energy beam transport lines. To ensure the safe operation of the BNCT02 accelerator, a machine protection system (MPS) was designed based on Yokogawa PLC and Experimental Physics and Industrial Control System (EPICS) software toolkit. The MPS adopts a redundant design, consisting of two completely independent subsystems with consistent main input and output signals. The test results show that the response time of the MPS is less than 1.6 ms, and it has the characteristics of high stability and reliability, which meets the operational requirements of the BNCT02 accelerator.