Algebraic dynamics is applied to treat Landau system. We consider the case
with the vector potential A = B(t)(-y, 0, 0) and the scalar potential phi =
-E(t)y +k(t)y(2), and find that the system has the dynamical algebra su (1
, 1) + h (3). With a gauge transformation the exact solutions of the system
are found, of which the quantum motion in y-direction represents a harmoni
c oscillator with a moving origin and a varying amplitude of width, the par
amertes of the gauge transformation are related to the amplitude, the veloc
ity potential and the expectations of y and p(y), respectively. The energy
of the system, the fluctuations of dynamical variables, the transition ampl
itudes between different states, and the Berry phase are calculated.