The observed high-field magnetization curves of $Sm_{2}Fe_{17}N_{3.0}$ at 4.2 K and 296 K are well reproduced by the calculation using the Sm-Fe exchange field $2mu extrm{B}H_{ex};=;320;K$ and two crystalline electric field parameters ${A_{0}}^{2}=;-910;K$ and ${A_{1}}^{0}=;200;K$. The calculation shows that during the magnetization process along the hard axis at 4.2 K, the Sm moment rotates toward the direction antiparallel to H when H < 110 kOe and then returns to the field direction with further increase of the field. At 296 K, the Sm moment rotates toward the direction antiparallel to H monotonously with increasing field and finally becomes antiparallel to H when $H{geq}H_{A}=210;kOe$. The particular magnetization process of the Sm moment can be explained by the field-induced noncollinear coupling between the spin and orbital moments of the Sm ion.