In order to understand the effect characteristics of different mulching films and fertilization quantities on soil and crop and the relative importance of plastic film mulching on increasing soil temperature and conserving soil moisture in cold and arid region, a field experiment with randomized block design of two factors was employed to analyze and compare the effect differences of broad and narrow degradable films, broad and narrow ordinary plastic films, and fertilization quantity on soil moisture, soil temperature, maize growth and development, and maize yield. The results showed that broad and narrow degradable films and ordinary plastic films all had significant temperature-increasing and moisture-holding effects. Fertilization also had certain temperature-increasing and moisture-holding effects. The different maize growth stages were all earlier in the treatments mulched with broad and narrow degradable films and ordinary plastic films than that in CK, but fertilization did not affect maize growth stages. The promoting effect of mulching treatments on the maize growth appeared at the early stage of maize growth, but that of fertilization treatments mainly at the middle and later stages of maize growth. Mulching treatments significantly increased maize yield and WUE and broad film mulching treatments were significantly better than narrow film mulching treatments. The reason of mulching treatment increasing maize yield was mainly due to the increase of weight per hundred kernels, but the reason of fertilization treatment increasing maize yield was due to the increases of both kernel number per ear and weight per hundred kernels. The major factor of limiting maize growth and development was low temperature and the yield-increasing effect of film mulching was bigger than that of fertilization in cold and arid region. The interaction effect of film mulching and fertilization was not significant.