In this paper, the properties of the SU3 wave functions, introduced by Elliott in 1958, are discussed in some detail. By means of the commutation relations of the infinitesimal operators of SU3 group, the internal wave functions x(α(λμ))K) can be calculated in a comparatively simple manner. With the use of the internal wave functions x(α(λμ))K), a formula of the fractional parentage coefficients for the SU3 wave functions Ψ(α(λμ))KLM) is obtained. As examples the SU3 wave functions of 2 or 3 nucleons in sd shell are calculated.