The invention discloses an 
oxygen sensor-based 
urea jet control device for a diesel and a control method for 
urea jet control device, and relates to a post-treatment 
selective catalytic reduction (SCR) control technology of the diesel. The jet control device comprises an 
electric control unit (ECU), a 
urea box, a urea pump, a urea 
nozzle, an SCR box, an SCR box front air 
exhaust pipe, an SCR box rear air 
exhaust pipe, an SCR box front 
oxygen sensor and an SCR box rear 
oxygen sensor, wherein the SCR box front 
oxygen sensor and the SCR box rear 
oxygen sensor are respectively arranged on the SCR box front air 
exhaust pipe and the SCR box rear air exhaust 
pipe; closed-
loop control of jet volume of urea, namely NH3 is realized through signals of the SCR box front oxygen concentration sensor and the SCR box rear oxygen concentration sensor; a calibration value of 
NOx discharged from 
tail gas is corrected and compensated through the signals of the SCR box front 
oxygen sensor and the SCR box rear oxygen sensor; and the reaction efficiency of the SCR box is judged through the signals of the SCR box front oxygen sensor and the SCR box rear oxygen sensor, and the jet volume of the NH3 is accurately controlled; and the price of the oxygen sensor is far lower than that of a 
NOx sensor. By the urea jet control device, urea jet is controlled through the signals of the SCR box front oxygen sensor and the SCR box rear oxygen sensor, so that the cost of post-treatment systems is greatly reduced.