Power-shift multiple-stage transmission of planetary design for a vehicle for arranging between a drive shaft and an output shaft, the multiple-stage transmission having two parallel shaft trains (WS1, WS2), six shifting elements (K1, K2, K3, K4, B1, B2), two spur gear stages (STS1, STS2) and three planetary gear sets (PS1, PS2, PS3), the planetary gear sets (PS1, PS2, PS3) in each case having a sun gear (SO1, SO2, SO3), an internal gear (HO1, HO2, HO3) and a planetary carrier which is combined in a spider (ST1, ST2, ST3) with a plurality of planetary gears, it being possible for the two shaft trains (WS1, WS2) to be connected to one another via the two spur gear stages (STS1, STS2), it being possible for different transmission ratios to be brought about between the drive shaft and the output shaft by way of selective engagement of the six shifting elements (K1, K2, K3, K4, B1, B2), with the result that a plurality of forward gears, in particular nine forward gears, and at least one reverse gear can be realised, the three planetary gear sets (PS1, PS2, PS3) and the drive shaft being arranged on a first shaft train of the two parallel shaft trains (WS1, WS2), and the output shaft being arranged on a second shaft train of the two parallel shaft trains (WS1, WS2), characterized in that a sun gear of a second planetary gear set of the three planetary gear sets (PS1, PS2, PS3) and the drive shaft are connected to one another fixedly so as to rotate together and form a first connecting element, a sun gear of a first planetary gear set of the three planetary gear sets (PS1, PS2, PS3), a first spur gear (ST2a) of a second spur gear stage of the at least two spur gear stages (STS1, STS2) and an internal gear of the second planetary gear set being connected or being capable of being connected to one another via a second, fourth and fourteenth connecting element, the second, fourth and fourteenth connecting element (2, 4, 14) having a common connecting point and, furthermore, the second connecting element being connected to the sun gear of the first planetary gear set, the fourth connecting element being connected, furthermore, to the internal gear of the second planetary gear set, and the fourteenth connecting element being connected, furthermore, to the first spur gear (ST2a) of the second spur gear stage, an internal gear of the third planetary gear set of the three planetary gear sets (PS1, PS2, PS3) and the spider of the second planetary gear set being connected to one another fixedly so as to rotate together and forming a third connecting element, a first spur gear (ST1a) of a first spur gear stage of the at least two spur gear stages (STS1, STS2) and an internal gear of the first planetary gear set being connected to one another and forming a fifth connecting element, a second spur gear (ST1b) of the first spur gear stage and the output shaft being connected and forming a sixth connecting element, a spider of the first planetary gear set and the drive shaft being connected to one another and forming a seventh connecting element, a second spur gear (ST2b) of the second spur gear stage and the output shaft being connected to one another and forming an eighth connecting element, a second shifting element of the six shifting elements (K1, K2, K3, K4, B1, B2) being arranged in the power flow between the drive shaft and a spider of the third planetary gear set, a third shifting element of the six shifting elements (K1, K2, K3, K4, B1, B2) being arranged in the power flow between the the fourth connecting element and the spider of the third planetary gear set, a fifth shifting element of the six shifting elements (K1, K2, K3, K4, B1, B2) being arranged in the power flow between the spider of the third planetary gear set and a transmission housing, and a sixth shifting element of the six shifting elements (K1, K2, K3, K4, B1, B2) being arranged in the power flow between the sun gear of the third planetary gear set and the transmission housing.