Small crystal FeZSM-5 was synthesized by a two-stage varying-temperature technique, in which the reaction mixture was first kept at a relatively low temperature for a period, and then abruptly raised to the required crystallization temperatures. The effects of sol concentration, alkalinity, temperature as well as templates on crystal size were investigated. The results showed that the crystal size of the ultimate product could be tailored through controlling the nucleation period and rate in the first stage via changing alkalinity, templates, and water content in hydrogel. Typically, a product with uniform crystal size of about 300 nm was obtained from a reaction mixture with molar ratio 1SiO(2) : 0.02Fe(2)O(3) : 0.6R : 0.3Na(2)O : 50H(2)O (R = n-butylamine) under suitable crystallization conditions for 50 h.