Abstract: We find by the wavelet transform that the classical plane light wave of linear polarization can be decomposed into a series of discrete Morlet wavelets. In the theoretical frame, the energy of the classical light wave becomes discrete; interestingly, the discretization is consistent with the energy division of P portions in Planck radiation theory, where P is an integer. It is shown that the changeable energy of a basic plane light wave packet or wave train is $H_0k =np_0k \omega (n=1, 2, 3, \ldots; k=\vert  k\vert$), with discrete wavelet structure parameter n, wave vector k and idler frequency ω , and a constant p_0k. The wave-particle duality from the Mach-Zehnder interference of single photons is simulated by using random basic plane light wave packets.

Key words: classic plane light wave, discrete wavelet structure, discrete energy