Abstract: Based on Collins formula,an analytical propagation expression for Hermite-Laguerre-Gaussian(HLG) beams through a paraxial optical ABCD system is derived and used to study their propagation properties in free-space and through a thin lens.The results show that,apart from the mode indices m,n,it is necessary for HLG beams to introduce a new parameter α,which affects their intensity distribution and symmetry property.HLG beams preserve their shape upon propagation.There is a focal shift in HLG beams which is independent of the parameters m,n,and α,which means that HLG beams with different values of m,n,α are focused at the same place.The M2 factor of HLG beams is also given.