A projection lens adjustment module applicable to a projection lens is provided. The projection lens includes a first assembly and a second assembly. The projection lens adjustment module includes a flexible connection line, an adjusting element and a driving mechanism. The flexible connection line has a first end and a second end opposite to each other. The adjusting element is connected to the first end. The driving mechanism is connected to the second assembly and the second end. When the adjusting element drives the first end to move along a first direction thereby leading the second end to move along a second direction non-parallel to the first direction, the second end drives the second assembly to move along an optical axis direction of the projection lens relative to the first assembly through the driving mechanism.