A one-year field experiment was conducted to evaluate the effects of plastic film mulching (FM) and nitrogen application rates applied to rain-fed maize fields on net global warming potential (Net GWP) and greenhouse gas intensity (GHGI) at the Changwu Agricultural and Ecological Experimental Station. Both GWP and GHGI were affected by the plastic film mulching and nitrogen application rate. Under the FM treatment,maize yield ranged from 1643 to 16699 kg·hm~(-2),the net GWP (CO_2-eq) ranged from 595 to 4376 kg·hm~(-2)·a~(-1),and the GHGI (CO_2-eq) ranged from 213 to 358 kg·t~(-1). The grain yield of maize,net GWP and GHGI for the UM (no mulching) treatment were 956 to 8821 kg·hm~(-2),342 to 4004 kg·hm~(-2)·a~(-1)and 204 to 520 kg·t~(-1),respectively. The results suggested that plastic film mulching could simultaneously improve grain yield and decrease GHGI in rain-fed cropland along with nitrogen fertilizer of 250 kg·hm~(-2).