A series of nanocrystalline powders Zn06CoxFe24-xO4 ( x=0—030) was synthesized by the solgel technique. The structure and mag netic properties was investiga ted and analyzed through the xray diffraction (XRD) patterns and the vibrating sample magnetometer (VSM). The experimental results show that αFe2O3 tra nsitio nal phase appears in the temperature range from 550℃ to 800℃. Single-phase zinc-cobalt ferrites with a spinel structure are obtained when the temperature is beyond 800℃. With relatively higher values of the cobalt content x=0075 — 015, the specific saturation magnetization climbs up at first and then falls d o wn with the increase of the cobalt content. The coercive force strength Hc of Zn06CoxFe24-xO4 reaches its highest value 47520A/m when x=0075 at 1300℃. Hc increas es slowly with temperature near 1200℃ when x≥015 and remains in a flat s tate at 1200—1300℃ and moderate increase is obtained by increasing the x value. High specific saturation magnetization and coercive force can be obtained simultaneo usly when the cobalt content is near 010