The optimization of collimator with 30 MeV cyclotron as neutron source and <sup>181</sup>Ta as its proton target. cyclotron assumed work at 30 MeV power with 1 mA and 30 kW operation condition. Criteria of design based on IAEA’s recommendation. Using MCNPX as simulator, the result indicated that with using <sup>181</sup>Ta as target material with 0.55 cm thickness and 19 cm diameter, 25 cm and 45 cm PbF<sub>2</sub> as reflector and back reflector, 30 cm <sup>32</sup>S as a moderator, 20 cm <sup>60</sup>Ni as fast neutron filter, 2 cm <sup>209</sup>Bi as gamma filter, 1 cm <sup>6</sup>Li<sub>2 </sub>CO<sub>3-</sub> polyethylenes as thermal neutron filter, and 23 cm diameter of aperture, an epithermal neutron beam with intensity 4.37 x 10<sup>9</sup> n.cm<sup>-2</sup>.s<sup>-1</sup>, fast neutron and gamma doses per epithermal neutron of 1.86 x 10<sup>-16 </sup>Gy.cm<sup>2</sup>.n<sup>-1 </sup>and 1.93 x 10<sup>-13</sup>Gy.cm<sup>2</sup>.n<sup>-1</sup>, minimum thermal neutron per epithermal neutron ratio of 0.003, and maximum directionality 0,728, respectively could be produced. The results have passed all the IAEA’s criteria.