The magnetic field effects on the autocatalytic reduction of nickel ion by the hypophosphite ion in aqueous solution were explored. The reaction behaviors of the autocatalytic reduction of nickel ion were well interpreted by the Langmuir-Hinshelwood adsorption model. The results indicated that both the rate constant of the free-radical recombination reaction and the rate constants of adsorption and desorption reactions were affected by the magnetic field. At fixed initial pH 5.5 and 0.037 M succinic ion, the theoretical analyses correlated well with the experimental results and a semiempirical rate equation for the steady rate was obtained as r(s) = 0.0482 exp(-14090B/RT)[1.0178 exp(+12960B/RT)[Ni2+]/(1+1.0178 exp(+12960B/RT)[Ni2+])] where B is the magnetic flux density in units of tesla and T is the absolute temperature of 304 K. Both the apparent frequency factor and the apparent activation energy decreased with the magnetic field. The reaction behaviors of the autocatalytic reduction of nickel ion were also affected by the initial pH and initial concentration of the succinic ion of the deposition solution; however, the magnetic field effects with respect to the initial pH and initial concentration of the succinic ion were insignificant.