Organic light emitting display device and driving method thereof

An organic light emitting display device includes an organic light emitting element emitting light, a driving transistor configured to control a driving current supplied to the organic light emitting element, a first switch transistor configured to transfer a voltage input through a data line to a first node of the driving transistor, a second switch transistor turned on/off simultaneously with the first switch transistor to connect a second node of the driving transistor and a sensing line, a sensing capacitor connected to the sensing line to store a sensing voltage during an organic light emitting element threshold voltage sensing period, and a first switch configured to disconnect the sensing capacitor from the sensing line during a period in which sensing data for sensing a threshold voltage of the organic light emitting element is input to the data line and to connect the sensing capacitor to the sensing line during the organic light emitting element threshold voltage sensing period.