Abstract: In order to investigate the present situation of plastic film used and to understand its residual contamination in Ulanqab city, two methods of questionnaires and field samples collected were used to investigate the plastic film residue problem in two typical regions of this city. The current using situation of the plastic film was analyzed combined with the statistical data and the results showed that： In Ulanqab city, the covering area and the used volume of film firstly linear decreased and then stably increased, and the trend was like ＂V＂ from 2001 to 2010. In 2005, the covering area and the used volume of film reached trough, and decreased to 42.02% and 40.28% than in 2001, the covering area and the used volume of film in 2010 increased 67.60% and 93.54% than in 2005. Dispersed manage by individual farmer is the main model in Ulanqab city and the farmland ploughed depth was less than 25cm. The residual plastic film mostly contained in 0-20cm layers and the residual amount in 0- 30cm was mainly affected by the residue amount in 0-20cm. The plastic film used amount is 3.0-3.5kg/667m2 and residual amount is 0.8-6.4kg/667m2 in 0-30cm. Our initial view was that the plastic film using can not pollute the soil or not have negative effect on crops growth, but we must on guard the pollution of environment and residual plastic film caused by the increasing of the film covering area and the used volume. There was not polythene film collector in Ulanqab city, the residual plastic film was taken from farmland by harrowing and rolling, and it decreased by the more times harrowing and rolling. Suggestions for the optimization of Ulanqab city, with cropping system optimized, reasonable rotation, the late promotion technology promoted, biodegradable plastic film used, polythene film collector researched or imported, and so on, the hazards of the residual plastic film should be corrected understanding through the propaganda and training, policy guidance and legal guarantee, which can reduce the pollution of the residual plastic film greatly.