Projection lens and vehicle-mounted HUD provided with projection lens

The invention provides a projection lens and a vehicle-mounted HUD provided with the projection lens. The projection lens sequentially comprises a first lens group with a positive focal length, a diaphragm, a second lens group with a positive focal length, a light splitting device and an image source from the amplification end to the reduction end, wherein the first lens group comprises a first lens, a second lens and a third lens which are sequentially arranged from the amplification end to the reduction end; the second lens group comprises a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from the amplification end to the reduction end; light on the image source side sequentially passes through the light splitting device, the second lens group,the diaphragm and the first lens group to reach the object side for imaging. In addition, the projection distance of the projection lens ranges from 0.1 m to 0.12 m. According to the invention, the problem of lens out-of-focu