The invention relates to a solid magnetic heavy metal ion separation material and a preparation method of the separation material. Epoxy chloropropane and triethylene tetramine perform a polymerization reaction in the presence of a ferroferric oxide microsphere to generate linear high polymer chains; the surface of the ferroferric oxide microsphere absorbs and is wound with the linear high polymerchains in situ; the high polymer chains are further cross-linked by using glutaric dialdehyde in methylbenzene, so that the surface of the ferroferric oxide microsphere is coated with the high polymer chains stably; an iminodiacetic acid group is connected to a high polymer chain net on the surface of the ferroferric oxide microsphere via a dialdehyde substance, so that the surface of the ferroferric oxide microsphere is coated with the high polymer chain net containing rich active groups such as -N(CH2COO-)2, -NH2, -NH- and -OH; the trapping and absorbing capacity on heavy metals is greatlyimproved; the material has excellent magnetic separation performance; the subsequent separation is simple; continuous absorption and separation operation can be achieved; and the material is convenient in industrial application and popularization.