This invention discloses a portable electrical grease gun which relates to electric tool field. The portable electrical grease gun according to the present invention, in which conventional slide block assembly driving structure is replaced by a crank link mechanism. As a result, the structure of the product is compact and simple. The crank link mechanism is constructed at low cost. The friction is low during operation. The operation is stable and reliable. It is easy for bulk production. In addition, the volume of the portable electrical grease gun according to the present invention is small so that it is easy to take and operate conveniently.