Safety and nuisance-free bio-gas liquid application method

The invention relates to a method for irrigating vegetable with marsh liquid, wherein said method comprises that: collecting and transmitting the ferment marsh liquid to the field; when N:P2O5:K2O of marsh liquid is 1:0.4-0.6:0.8-1. 5, using 2000-4000kg marsh liquid of each unit as base fertilizer to be fed into vegetable field; adding 2000-2500kg marsh liquid via demand, and adding composite fertilizer and aquacare with 0.3-0.6kg/100kg marsh liquid. The invention can realize non-pollution irrigation.