Abstract: A reflective type light valve projection device comprises an incident light source, a first and a second dichroic beam splitters/combiners, three light valves of the three primary colors and a projection lens. The light source provides a white light. The first dichroic beam splitter/combiner can reflect the first primary color and transmit the other two primary colors, and the second dichroic beam splitter/combiner can respectively reflect and transmit the two primary colors passing through the first dichroic beam splitter/combiner, hence completely separating the three primary colors. After the three primary colors are respectively modulated and reflected by the three light valves, they are combined by the first and second dichroic beam splitters/combiners to form a full color image, which is finally projected out by the projection lens. The optimum full-color projection effect can thus be accomplished with the least component.