The invention relates to power automatic weighing equipment and a weighing method thereof. The powder automatic weighing equipment comprises a powder feeding mechanism, a weighing sensor, a stirring mechanism, a micro powder feeding mechanism, a weighing controller and a material cup, wherein the weighing equipment adopts a mass method principle and automatically weighs the incoming power piece bypiece according to requirements of product specification parameters; the feeding mechanism comprises two stages of power transmission which are respectively used for fast feeding and accurate feeding; the weighing sensor feeds back the current weight data to a control system in real time online; the weighing controller adopts closed-loop control, and control on-off of the feeding mechanism through reading the weight data; the stirring mechanism is used for increasing the fluidity of the powder in a hopper; a dust concentration detection instrument detects the concentration of the powder online and feeds back the date to the control system in time; and an electrostatic eliminator is placed at the powder hopper and a blanking port and used for eliminating static electricity. The power automatic weighing equipment liberates workers from the purely manual operation environment, improves the production efficiency, saves labor resources and also avoids bad influences imposed on the body health by dust particles at the same time.