In this paper general system structure in the form of block diagram as well as signal flow graph (SFG) for multivariable nonlinear systems has been developed and the corresponding matrix formulation has also been done. From the review of several literature it confirms that the structure developed in this paper may be most general and most suitable for the analysis of self oscillations and signal stabilisation of multivariable nonlinear systems. The ease of application of the structure in the prediction of self oscillation has been illustrated through the example of a two dimensional nonlinear system.