Using the high sensitivity differential sensor,we collected 80 groups of fluctuating signals in vertical upward gas/liquid two phase flow. We established the general description method of chaotic attractor morphological characteristic using referenced sections, and then put forward a new flow pattern classification method of gas/liquid two phase flow by combining the chaotic attractor morphological feature parameters of different dimensions. The study shows that the proposed method can get a good clustering of gas/liquid two phase flow patterns, including the complex transitional flow pattern, and it implies that the method of chaotic attractor morphological characterization is an effective approach to study nonlinear time series in practice.