The characteristics of the cities in China and the policy and status of the development of rail transit systems in China are analyzed, which shows that the rail transit systems to be built in medium scale cities in China have such features as mediumlow transportation capacity, high cost efficiency in construction and operation, environmental friendliness, high operation efficiency and high safety. The adaptability of different rail transit systems, including “steel wheel + steel rail” rail transit system with Type B or Type C elevated train, straddle monorail system, linear motor system, “rubber wheel + guide rail” system and mediumlow velocity magnetic elevation system, to the medium scale cities in China are analyzed, and comprehensive technological and economical comparison and contrast is made among the mentioned rail transit systems. It is concluded that the straddle monorail system should be the dominant mode of rail transit systems with medium transportation capacity. Finally, recommendations are made on how to promote the development of straddle monorail system in China.