Taking the generalized time-dependent harmonic oscillator (GTHO) and s
ingular time-dependent harmonic oscillator (STHO) as illustrative exam
ples, we discuss the connection between the quantum basic invariants a
nd classical Noether's theorem and, for the system, find: (1) The clas
sical basic invariants and general form of classical invariants. (2) T
he current algebra and corresponding operator algebra. (3) A kind of c
onverse of the Noether's theorem. (4) The connection between the so-ca
lled symmetry algebra ({G(k)} algebra) and the classical current algeb
ra through the operator algebra.