A detection method of a pixel circuit, a driving method of a display panel, a display device and a pixel circuit are provided. The pixel circuit includes a driving transistor, and the detection method includes a writing phase and a reading phase. The writing phase includes: writing a reference data voltage to a gate electrode of the driving transistor, and writing a first detection writing voltage to a first electrode of the driving transistor to turn on the driving transistor; and the reading phase includes: upon the driving transistor being turned off after a first predetermined time after writing the first detection writing voltage, reading a voltage of the first electrode of the driving transistor to obtain a first detection reading voltage for obtaining a threshold voltage of the driving transistor.