Taiwan has inspired many a propaganda poster in China. Two main themes are evident: Protection of the coasts and re-conquest of the island.
The posters exhorting vigilance against a sea-borne threat don't usually finger Taiwan, but the reference is obvious. While militiamen scrutinize the horizon, fishermen at sea keep a rifle at their shoulders. "Heighten your Vigilance," "Protect the Motherland," and "Be Ready to Annihilate Invaders at any Moment" are the operative phrases. One can't totally blame the communists for their paranoia. Re-taking the mainland was indeed long an official objective of the Guomindang, Taiwan's ruling party. It will be abandoned reluctantly in the 80's, the perspective having become illusory.
For its part, Communist China has never renounced taking back the "rebel province." Almost all posters for the re-conquest of Taiwan utilize the same slogan: "We Must Liberate Taiwan." Warships, warplanes and missiles often appear in the background. If today the posters have disappeared from the walls, the slogan remains. "We Must Liberate Taiwan" is probably the sole propaganda slogan to convey a deeply held conviction of the Chinese people itself. "Taiwan is Chinese and must return to the Motherland by whatever means necessary" is one of the most widely held opinions on the mainland today.