The invention discloses a vehicle-mounted unpowered urban environment air purifying device which comprises a carrier which can be connected with a vehicle hub. A sealed air purifying chamber of an annular structure is arranged on the carrier, multiple diversion devices delivering air into the air purifying chamber are arrayed on the outer periphery of the air purifying chamber, and a filtering device for filtering air is arranged in the air purifying chamber. Traveling power of a vehicle itself is utilized as an air circulating power source, so that energy consumption is zero; by arranging the diversion devices, air on two sides of a vehicle body can be sucked into the air purifying device; by arranging the filtering device, pollution of air caused by tiny dust and pm2.5 in the air can be lowered effectively. The air purifying device is reasonable in design, attractive and practical in appearance and convenient to mount and clean and can be cleaned directly by using water.