The microtribological properties of Langmuir-Blodgett (LB) monolayer films in AC and DC electric fields have been investigated using scanning force microscopy (SFM). Friction and wear characteristics of LB films can be controlled and improved by an external electric field. In a DC held, the friction force of the LB film increases with the external voltage, and its wear-life is significantly shortened. On the other hand, in an AC field, friction force is a function of AC voltage and frequency. With a special combination of voltage and frequency, the friction force almost approaches zero, and the wear-life of the LB film is greatly extended.