a hydraulic system and a controller; the hydraulic system comprising: a plurality of proportional pressure reducing valves, a calibration reversing valve, and a pressure sensor; the calibration reversing valve comprising a plurality of reversing units, an output end of each proportional pressure reducing valve being respectively connected with an input end of one corresponding reversing unit; first output ends of the reversing units each being connected with one working oil path, and second output ends of the reversing units each being connected with one detection oil path via a connection pipeline; the pressure sensor being arranged in the detection oil path;

the controller being respectively connected with the plurality of proportional pressure reducing valves, the calibration reversing valve and the pressure sensor, and configured to control the reversing unit for reversing, to input pilot oil outputted by a corresponding one of the plurality of proportional pressure reducing valves into the detection oil path; acquire a pilot oil detection pressure acquired by the pressure sensor, and perform calibration processing on the corresponding one proportional pressure reducing valve according to the pilot oil detection pressure and an output pressure value of the corresponding one proportional pressure reducing valve.