A prepreg tack testing de vice is established to study the automatic placement process characteristics of the NY9200GA epoxy prepreg tack. Prepreg tack between layers under different placement processing parameters is discussed based on onefactoratatime approach. Orthogonal test is used to determine the influence of placement processing parameters on tack. The results indicate that the prepreg tackbetween layers increases initially then decreases with rising of placement temperature. Tack peak appears at 40 ℃. Both the increase of pressure and the decrease of feed rate lead to the increase of the prepreg tack between layers. The influence of temperature on tack is the largest. Pressure takes the second place to prepreg tack. Furthermore prepreg tack relates to exposure time and fiber direction. The longer the exposure time at room temperature is, the lower the prepreg tack will be. Prepreg tack between layers rises gradually with the increasing intersection fiber angle of the adjacent prepreg layers. The tack of 0°/90° layers is nearly double of the figure of 0°/0°layers. 