用屏栅电离室测量了入射中子能量为５．１ＭｅＶ的５８Ｎｉ（ｎ，α）５５Ｆｅ核反应的α粒子角分布，２３８Ｕ裂变电离室作中子注量率的测量，测得该能点５８Ｎｉ（ｎ，α）５５Ｆｅ的总截面为（４７．４±５．０）ｍｂ．用中国核数据中心推荐的理论计算程序ＵＮＦ计算了在１—８ＭｅＶ能区５８Ｎｉ（ｎ，ｐ）５８Ｃｏ，５８Ｎｉ（ｎ，α）５５Ｆｅ的反应截面和入射中子能量为５．１ＭｅＶ的５８Ｎｉ（ｎ，α）反应角分布．理论和测量数据的比较说明，用复合核模型来描写该能点的角分布是可行的． The α particle angular distribution of 58Ni (n, α) 55Fe nuclear reaction with incident neutron energy of 5.1MeV was measured by using a screen grid ionization chamber. The 238U fission ionization chamber was used to measure the neutron fluence rate. The energy point 58Ni ( n, α) 55Fe has a total cross section of (47.4 ± 5.0) mb. The reaction cross sections of 58Ni (n, p) 58Co and 58Ni (n, α) 55Fe in the 1 8MeV energy range and the diffraction peaks of 58Ni (n , Α) reaction angle distribution. The comparison of theory and measurement data shows that it is feasible to describe the angular distribution of this energy point by the composite kernel model.