A vehicular projection system includes plural information collectors, a time-division multiplexing device and a projection mechanism. The plural information collectors are used for outputting driving information. The time-division multiplexing device includes plural wireless transmission modules. The time-division multiplexing device determines the transmitting sequence of plural information collectors according to the receiving sequence of wireless transmission requests from the plural information collectors. Moreover, the time-division multiplexing device determines the suitable wireless transmission modules according to the file properties of the driving information and the wireless transmission capabilities of the plural information collectors. Since the plural information collectors can simultaneously transmit driving information to the time-division multiplexing device through different wireless transmission modules, the wireless transmission efficiency is enhanced.