Abstract: To explore the practicality of degradable films and select one between different degradable films by superior, the comparisons on the soil temperature, moisture, characters and outputs by ordinary plastic film, different degradable films and open cultivation under common natural conditions has been discussed through the method of contrastive analysis. The results showed that: each mulching group could increase the soil moisture in the 0-40 cm profile, the soil temperature in 0-25 cm profile in the earlier growth duration of corn compared with open-air, this heat preservation could last for 65 days, based on the preservation effects of water and heat, these groups could rank from higher to lower as follows: ordinary plastic film and degradable film 1 > degradable film 2 > open cultivation. Their increase rates of degradable film 1, plastic film and degradable film 2 respectively were 19.5%, 22.0% and 13.1%, the degradable film1 had the similar influence. Thus, degradable film 1 replace plastic film is operational.