A projection lens assembly is provided. The projection lens assembly includes, sequentially along an optical axis from a source-side to an image side, a first lens having a positive refractive power; a second lens having a negative refractive power, where a source-side surface and an image-side surface of the second lens are concave surfaces; a third lens having a positive refractive power or a negative refractive power; and a fourth lens having a positive refractive power, where an image-side surface of the fourth lens is a convex surface. A total effective focal length f of the projection lens assembly and an effective focal length f1 of the first lens satisfy: 2.0