Defining the noncommutative zero-curvature equation, we show that many soliton equations can be written in this form. We demonstrate this by showing that various soliton equations are derived from this equation. The derived soliton equations differ according to different choices of manifolds in the reduction of the noncommutative zero-curvature equation.The Moyal quantization is known to give an alternative to the quantization. Lately people are interested in noncommutative space-time, which is also formulated in the same way as the Moyal quantization [1]. The Moyal quantization expresses quantum theory not by operators but by functions of the phase space. The purpose of this note is to show that the noncommutative zero-curvature equation, which is defined by using the product, can be an alternative to the zero-curvature equation of the matrix-valued potentials.The soliton equations can be formulated in various ways, and one of which is the AKNS formulation [3,4]. This is regarded as the geometrical zero-curvature equation. This is given bywhere A µ = A µ (x 0 , x 1 ; ζ), (µ = 0, 1) are the Lie-algebra valued matrices. These potentials include a parameter ζ, and the specific expansion in terms of the parameter yields a corresponding soliton equation. We define the product by(2) * Speaker.