The present disclosure provides a pixel circuit, its driving method, an OLED display panel and a display device. The pixel circuit includes: a display driving module configured to, within a time period and under the control of a first scanning signal from a first scanning line, a second scanning signal a the second scanning line and a control signal from a control line, compensate for a threshold voltage of a driving transistor with a data signal from a data line and a second signal from a second signal source, so that a light-emitting driving signal for the OLED is irrelevant to the threshold voltage of the driving transistor at a third stage of the time period; and a capacitive touch detection module configured to, within the time period and under the control of the first scanning signal and the control signal, detect a touch signal from a touch screen.