Neutron diffraction experiments have been carried out to study the magnetocrystalline anisotropy of two (2b and 2d) Tin sublattices and four (4/, Qg, 12 j, and 12k) Fe sublattices in ferrimagnetic compound Trr^Fei? (space group Рбз/ттс). We determine the temperature dependence of the magnitude and orientation of magnetization for each of the thulium and iron sublattices in the range (10-300) K. A spontaneous rotation (at about 90 K) of the Tin and Fe sublattice magnetizations from the c-axis to the basal plane is accompanied by a drastic change in the magnetization magnitude, signifying a large magnetization anisotropy. Both Tin sublattices exhibit an easy-axis type of the magnetocrystalline anisotropy. The Fe sublattices manifest both the uniaxial and planar anisotropy types. The sublattice formed by Fe atoms at the 4/ position reveals the largest planar anisotropy constant. The Fe atoms at the 12j position show a uniaxial anisotropy. We find that the inelastic neutron scattering spectra measured below and above the spin-reorientation transition are remarkably different.