A plastic optical lens assembly includes a first lens element, a second lens element and a cementing glue coating. A first spacing section is located between a first optical effective portion and a first engaging structure. A second optical effective portion is disposed correspondingly to the first optical effective portion. A second spacing section is located between the second optical effective portion and a second engaging structure. The first engaging structure is engaged with the second engaging structure. A reference space is between the first and the second spacing section. The cementing glue coating is at least disposed between the first and the second optical effective portions, and the first and the second lens elements are cemented by the cementing glue coating.